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FAMILIAR LECTURES 


ON 


CHEMISTRY. 


TOR SCHOOLS, FAMILIES, AND PRIVATE STUDENTS. 


BY MRS. LINCOLN PHELPS. 

PRINCIPAL OF THE PATAPSCO FEMALE INSTITUTE, MARYLAND. 

AUTHOR OF A SERIES OF WORKS ON BOTANY, NATURAL PHILOSOPHY AND CHEMISTRY, 
DESIGNED FOR BEGINNERS AND MORE ADVANCED STUDENTS. 


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3 


SECOND EDITION, 

REVISED AND CORRECTED BY THE AUTHOR. 


NEW YORK: 

PUBLISHED BY F. J. HUNTINGTON & CO. 
174 PEARL ST V REET. 

1842. 


Entered according to the act of Congress, in the year 1838, by 
F. J. Huntington & Co. 

in the Clerk’s office of the Southern District of New York. 



Jut i 










V; 




DEDICATED BY PERMISSION, 

TO 

DR. ROBERT HARE. 

To whose inventive genius Chemistry is indebted for many 
of its most valuable illustrations. 
















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' 






PREFACE. 


Chemistry is a most comprehensive science ;—while it in¬ 
structs philosophy in the constitution of matter, it teaches how 
to perform the most common operations in the business of life, 
such as the preparation of food, the warming and ventilation of 
apartments, soap making, washing, &c. The arts of dyeing, glass 
making, engraving, and of preparing medicines, have their found¬ 
ation in chemical science. 

From the intimate connection which subsists between the dif¬ 
ferent branches of Physical Science, the Author of this work has 
been naturally led from the study of one, to that of others ; and 
the pleasures and advantages she has derived from these pursuits, 
have induced the desire that they might be more generally appre¬ 
ciated and enjoyed, especially by her own sex. Her series of 
volumes on Botany, Natural Philosophy, Chemistry, and Geol¬ 
ogy, she is happy to believe, have been studied by many who 
would not have felt the courage to encounter more erudite works. 
Teachers, diffident of their own acquirements, have been taken 
by the hand, and guided along with their pupils, in paths which 
the Author had labored to free from difficulties. It is pleasant, 
to reflect that we are companions of the young, in their search 
after knowledge, when the mind, yet free from prejudice, is 
open to the reception of truth ; and that our thoughts thus become 
incorporated with their thoughts ;—it is a still higher satisfaction, 
to feel assured that, with scientific truths, may be implanted 
germs of piety, which will unfold themselves with the mental 
developement, so that the blossoms of the intellect, may be accom¬ 
panied by the fruits of the soul. 


VI 


PREFACE. 


To her sister, Mrs. Emma Willard, the Author is much 
indebted for many useful suggestions, incorporated into this work, 
and for the use of a valuable Manuscript on Chemistry, prepared 
under her direction, by Lieut. Wm. F. Hopkins, late Professor of 
Chemistry at the U. S. Military Academy, West Point. The 
principal authors consulted in the preparation of this volume are 
Turner, Hare, and Silliman. 


NOTE FOR THE SECOND EDITION. 


The matter in small type may be omitted in public examina¬ 
tions, and is intended less for study, than for reading after the 
pupil shall have gained a knowledge of the fundamental princi¬ 
ples of the science, by a thorough attention to the other parts of 
the book. 

Patapsco Female Institute , Maryland , 

Jan . 1, 1842. 


CONTENTS 


LECTURE I. Introductory. General views of Physical Sci- page. 

ence. Properties of matter.9 


PART I. 


IMPONDERABLES. 


LECTURE 11. 

General Remarks on the Imponderables. Heat. 




Expansion. Thermometer. 

17 

u 

III. 

Conduction of Heat. Radiation and Reflec¬ 




tion. Latent Heat. Liquefaction. Frigo- 




rific Mixtures. ...... 

30 

(( 

IV. 

Vaporization. Ebullition. Steam. Distilla¬ 




tion. Gases and Vapors. 

43 

u 

V. 

Light. Decomposition of Light. Illuminating, 




Heating, Coloring, and Magnetic Rays. 




Flame. Phosphorescence. .... 

57 

(( 

VI. 

Electricity. Galvanism, .... 

63 



PART II. 




INORGANIC CHEMISTRY - . 


LECTURE VII. 

Chemical Nomenclature. Affinity. 

77 

k 

VIII. 

Affinity continued. Laws of Combination. 




Theories of Atoms. Theories of Volumes. 

90 

u 

IX. 

Division of Ponderables. Simple electro-neg¬ 




ative substances. Oxygen. 

101 

It 

X. 

Chlorine. .. 

110 

ll 

XI. 

Bromine. Iodine. Fluorine. 

118 

it 

XII. 

Simple electro-positive substances. Hydrogen. 




Water.. 

126 

u 

XIII. 

Hydracids. ....... 

138 

u 

XIV. 

Nitrogen, and its compounds with oxygen. 

144 




viii 


CONTENTS. 


LECTURE XV. Compounds of Nitrogen with Hydrogen, &c. 157 

“ XVI. Carbon. Compounds of Carbon with Oxygen,&c. 163 

“ XVII. Compounds of Carbon with Hydrogen. . 176 

“ XVIII. Cyanogen or Carbon with Nitrogen. Boron. 186 

“ XIX. Silicon. Phosphorus. . . . • .195 

“ XX. Sulphur. Selenium.208 

“ XXI. General Observations on the metals. First 

Class of Metals, or those which form acids 
with oxygen. ...... 223 

“ XXII. Metals of the Second Class. Alkaline Metals. 

Order I. Metals which with Oxygen form 

the fixed alkalies..239 

“ XXIII. Second Class of Metals continued. Order II. 

Metals which with Oxygen form alkaline 

earths..248 

“ XXIV. Metals, Class III. Earthy Metals. - - 255 

“ XXV. Metals, Class IV. Whose oxydes are neither 

acids, alkalies nor earths. - 259 

tc XXVI. Fourth Class of Metals continued. - - 267 

“ XXVII. Fourth Class of metals continued. - - 278 

“XXVIII. Crystalization. Classification of Salts. Salts 

of the Oxacids. 290 

u XXIX. Salts of the Oxacids continued. ... 306 

“ XXX. Salts of the Hydracids..318 


PART III. 

ORGANIC CHEMISTRY. 

' 

“ XXXI. Vegetable Chemistry. Proximate Principles and 

Ultimate Elements. Vegetable Acids. - - 326 

“ XXXII. Vegetable Alkalies, Oils, Resins, &c. - - 337 

“ XXXIII. Alcohol, Ether, &c..346 

u XXXIV. Sugar,, Starch, Gum, etc. ----- 351 

“ XXXV. Fermentation. - 366 

u XXXVI. Animal Chemistry..371 


FAMILIAR LECTURES 

ON 

CHEMISTRY. 


LECTURE I. 

INTRODUCTORY. 

GENERAL VIEWS OF PHYSICAL SCIENCE.-PROPERTIES OF 
MATTER. 

The Sinter Sciences. 

1. The Physical Sciences are so intimately connected that 
the study of one throws light upon the others. Natural Philoso¬ 
phy, Natural History and Chemistry are sister sciences pos¬ 
sessing many characteristics in common, but each distinguished 
by peculiar traits. 

2. The object of all the Physical Sciences is the investigation 
of the material world. No object is too vast for the grasp of 
science, none too small for its observation. The celestial orbs, 
the lowly flowret and minute insect, are, alike, objects of scien¬ 
tific research ; and all, in their own peculiar way, proclaim, 

“ The hand that made us is divine,” 

3. Let us imagine the three sister sciences surrounded by 
objects of their several researches ;—We see Philosophy turning 
from the contemplation of the heavenly bodies , to cast an approv¬ 
ing look upon the steam-engine , and mechanical powers , or to 
examine with her optical glasses the structure of a mite, or some 
object in the far distant regions of space. Natural History , the 
priestess of nature, crowned with the flowers of all climates, calls 
around her all animated things , whether of the earth, the air or 
sea. She also claims as hers the rocky foundations of the earth , 
its metallic treasures , the diamond of the mine , and the ocean's 
pearl. 

1. Connection of the Physical Sciences. 

2. Their object and scope. 

3. The sister sciences. 

2 



10 


INTRODUCTORY. 


4. And what of all that is above, upon, or under the surface 
of the earth, belongs to Chemistry as her sister sciences have 
appropriated to themselves the works of nature and of art i 
Chemistry claims the elements , of which all material substances 
are composed ; she, under the direction of their great Creator, 
presides over their combination, and, at the appointed time, effects 
their dissolution, carefully garnering up her atoms, so that not 
one shall be lost. Chemistry, then, may be imagined as veiled 
from observation, and carrying on those secret processes of com¬ 
position and decomposition which are intimately connected with 
the operation and suspension of the vital powers in plants and 
animals. In obedience to her laws, inorganized matter assumes 
various forms of beauty and regularity, as in crystals and diamonds, 
and, at her command, the hardest rocks crumble into dust. 

5. The question is often asked, u does the study of the sciences 
tend to establish the mind in the truths of religion, and promote 
Christian humility ; or, rather, does not science put nature in the 
place of God, and heighten the pride of man, by filling him with 
lofty notions of his own powers, which can thus penetrate the 
mysteries of creation ?” We answer that such effects may arise 
from a superficial study of the sciences—he, who looks not 
beyond nature to nature’s God, who seeing a little, believes that 
he sees all of the mysteries of creation, cannot truly be called a 
philosopher. The discoveries of science demonstrate the exist¬ 
ence of physical laws which must have originated in one Om¬ 
niscient and Omnipotent mind ;—they exhibit nature as the mere 
creation of Almighty power, subservient to his will, and governed 
by his laws. Man, by the light of science, beholds himself as 
an atom in creation ; even his discoveries humble him ; for 
the more he learns of the wonders of nature, the more extensive 
seem the fields yet unexplored, and the more humble his own 
attainments. 

6; It is the office of science to explain appearances, and to teach 
man to distinguish them from reality. Thus, we learn from Astron¬ 
omy that the apparent motion of the heavenly bodies is not real, 
but caused by the motion of the earth ; we learn from Optics, 
that we do not see the real object before us, but its image de¬ 
picted on the back part of the eye, and, there, contemplated by 
the mind. Chemistry proves, that what appears to be the 

4. Province of Chemistry. 

5. Effects of the study of the sciences upon the human mind. Reli¬ 
gious influence of scienoe. 

6. Science teaches to distinguiah the apparent from the real. That 
matter is indestructible. Combustion not the destruction of atoms, but 
of combinations. Possible migrations of an atom. 



INTRODUCTORY. 


11 


destruction of matter is not such ; but, that when a body seems 
to undergo a process of dissolution, its particles are only set free 
to enter into new combinations, and that no atom, which has 
been created, is suffered to be lost. u One of the most obvious 
cases of apparent destruction is, when anything is ground to dust, 
and scattered to the winds. But it is one thing to grind a fabric 
to powder, and another, to annihilate its materials : scattered as 
they may be, they must fall somewhere, and continue, if only as 
ingredients of the soil, to perform their humble, but useful part, 
in the economy of nature. The destruction produced by fire, is 
more striking : in many cases, as in the burning a piece of char¬ 
coal or a wax taper, there is no smoke,nothing visibly dissipated and 
carried away ; the burning body wastes and disappears, while 
nothing seems to be produced but warmth and light, which we 
are not in the habit of considering as substances ; and when all 
has disappeared, except, perhaps some trifling ashes, we naturally 
enough suppose it is gone, lost, destroyed. But when we ex¬ 
amine more closely, we detect in the invisible stream of heated 
air which ascends from the glowing coal or flaming wax, the 
whole ponderable matter , united in a new combination with the 
air and dissolved in it. Yet, so far from being thereby destroyed, 
it has only become again what it was before it existed in the form 
of charcoal or wax, an active agent in the business of the world, 
and a main support of vegetable and animal life ; and is still sus¬ 
ceptible of running the same round, as circumstances may de¬ 
termine ; so that, for aught we can see to the contrary, the same 
identical atom* may lie concealed for thousands of centuries 
in a limestone rock ; may at length be quarried, set free in the 
lime kiln, mixed with the air, be absorbed from it by plants, and 
in succession, become a part of the frames of myriads of living 
beings, till some concurrence of events consigns it once more to 
a long repose, which, however, unfits it in no way from again 
resuming its former activity.”! 

7. Inquiries into the nature of compounds, and the various 
transmigrations of which matter is susceptible, must be deeply 
interesting to every intelligent mind. But it is not alone for the 
jileasures of science that its pursuits are recommended ; nor 

* An atom of carbon is here supposed;—limestone is carbonate of lime. 
In the lime kiln carbonic acid is expelled by heat; this acid combined 
with the air, furnishes food for plants • animals feed on plants, and 
thus the atom of carbon passes through the migrations which are 
above described. 

t Herschel. 


7. Relation of Chemistry to the useful arts. 



12 


INTRODUCTORY. 


can we assent to the definition of a writer on Political Economy, J 
viz ; u that a philosopher is a person whose trade it is to do 
nothing , and speculate on every thing.” Chemistry is not merely 
a grave pastime for philosophers ; it bears an important relation 
to the useful arts ; and most of the inventions of modern days 
owe their origin to this science, or depend on principles which 
Chemistry alone can explain. 

8. Art and science are mutually dependent on each other ; 
the former works , the latter thinks. It would be as absurd to 
contend which is the more useful to society, the working man or 
the thinking man, as whether the hands or the brain are the 
more necessary in effecting mechanical operations. Thinking and 
working should go together ; the more the working man thinks, 
or in other words, the more he combines science with mechani¬ 
cal skill, the more likely will he be to excel, and to improve on 
what others have done. The man of science who is skillful in 
manual operations, possesses a great advantage in being able to 
adapt to their proper use, his instruments of observation and 
experiment, to supply these deficiencies, or to invent new in¬ 
struments. 

9. Mechanical operations are a series of philosophical experi¬ 
ments. The soap boiler, in combining oil and water through 
the medium of an alkali, illustrates on a large scale the doctrine 
of Chemical Affinity. The glass maker exhibits chemical phe¬ 
nomena, in melting together and combining alkaline, saline, 
metallic and earthy materials ; in the effect of coloring matter 
upon the compounds thus formed ; and in cutting, grinding and 
polishing glass. The tanner , by a chemical process, converts the 
soft spongy skins of animals into leather, which is hard, tough, 
and impervious to water. The farmer in manuring his grounds, 
and in mixing soils of different kinds, is working on principles 
which he can only understand by a knowledge of the effects of 
chemical combinations. The physical sciences and the arts of 
life, must go, hand in hand, in the work of improvement. Every 
advance in science gives a new advantage to the arts ; and every 
improvement in the arts offers to science a fresh field of research, 
and new facilities for discovery. Thus, the philosopher and the 
artisan are mutually dependent on each other. 

10. The process of bleaching linen and cotton was long and 

f Smith, See Wealth of Nations, Book 1, Chap. 1, p. 15. 

8. Mutual dependance of art and science. 

9. Common operations effected on scientific principles. Soap boiling 
—glass making—tanning, &c. 

10. Practical applications of chlorine. 



INTRODUCTORY. 


13 


laborious, requiring weeks and even months for its completion, 
until by the discovery of chlorine , the manufacturer was present¬ 
ed with a liquid, which, by immersing the cloth in it for a few 
hours, produced the necessary effect. The same chemical 
agent, chlorine, is most usefully employed as a purifier of infect¬ 
ed atmospheres, thus preventing the contagion of dangerous 
diseases. 

11. The discovery of iodine may be traced to the observation 
of a soap boiler. In the refuse of soap ley, he discovered cer¬ 
tain corrosive properties for which he could not account. He 
applied to a Chemist, who, on subjecting the substance to analy¬ 
sis, discovered a new and important chemical element which he 
named iodine. The properties of this new substance attracting 
the attention of men of science, a sudden light was thrown upon 
subjects which, before, had appeared doubtful; and oxygen, 
instead of being, as formerly, considered the oidy supporter of 
combustion, is now, with iodine and chlorine, ranked among the 
elements thus distinguished. The origin of iodine being sought 
for, it was ascertained that the ley in whose residuum it is found, 
is obtained from the ashes of sea weed. If one salt water plant 
contains this substance, (reasoned the experimenter,) why may 
not others ? Among the marine plants in which iodine was 
found, is the sponge. Dr. Coindet of Geneva, knowing that 
burnt sponge was used by the inhabitants of the Alpine villages, 
as a remedy for that unsightly swelling of the neck called goitre , 
began to reflect that, possibly, the iodine contained in the ashes 
of the sponge might be medicinal. On giving iodine as a medi¬ 
cine, he found the goitre was soon dispelled. Reasoning from 
analogy, the same substance has been successfully applied in 
the case of other glandular swellings ; and an important med¬ 
ical agent has been thus added to the list of remedies for human 
diseases. 

12. A striking instance of the benefits of science, in alleviat¬ 
ing human suffering, is to be met with in the needle manufacto¬ 
ries of England. The workmen are obliged to breathe an at¬ 
mosphere filled with minute particles of steel, which fly from the 
grindstones, used in pointing the needles. The irritation produced 
by this dust on the lungs caused consumption. Various expe¬ 
dients were resorted to ; but no gauzes or screens could exclude 
this fine and penetrating dust. At length the magnetic influence 
was resorted to, and masks of magnetized steel wire gauze were 

11. Discovery made by a soap boiler. Effect of the discovery of 
iodine upon chemical science. Reasonings which lead to a discovery of 
the medicinal properties of iodine. 

12. Application of the magnetic power. 

2 * 



14 


INTRODUCTORY. 


constructed ; the floating atoms of steel being thus repelled , the 
workman now breathes freely, in the assurance that he is not in¬ 
haling a fatal atmosphere. 

13. The safety lamp , the lightning rod, the life boat, are gifts 
presented to man by science. We shall find in our researches 
into chemical science, that it is not only deeply interesting, as un¬ 
folding the laws and secret operations of nature, but eminently 
useful, considered in its relation to the diseases and wants of man 
and the progress of human improvement. 

14. In remarking upon the advantage of chemical science and 
its claims to attention, we have but slightly touched upon the 
effect which scientific pursuits must have on the mind itself , exercising 
a healthful and invigorating influence, and bringing into action 
and disciplining the intellectual powers. In considering the va - 
riety of the works of creation , the grand and the minute so harmoni¬ 
ously combined, and the system by which the whole universe is 
connected in an infinite series of relations ; in observing the 
readiness with which the human mind seizes upon facts which 
unfold these dependencies and relations, and the elevation and 
enlargement which such studies give to the soul, we are led to 
believe, that, as the earthly parent surrounds his child with the 
instruments and means of knowledge, so our Almighty Father 
made, beautified and enriched the material world, that He might 
thus, give lessons of wisdom to His children, and afford scope for 
the intellectual energies with which he had endowd them. Or 
rather, following the order of creation as revealed in scripture, 
man was last created, that he might behold, admire and study the 
works which God himself had pronounced u good.” 

15. Chemistry begins where the other natural sciences end. 
For example, Natural Philosophy considers the mechanical prop¬ 
erties of matter ; Natural History examines the external organa 
or form of objects, with a view to their classification ; while 
Chemistry, penetrating to their internal particles, examines their 
constitution. 

16. Chemistry teaches what are the elements of which matter 
is composed, the properties of these elements and their laws of 
combination; it also shows what are the component parts and 
properties of compound substances. 

17. The foundations of chemical science are observation , ex- 
periment and analogy. By observation , facts are noted and impressed 

13. Other applications of scientific discoveries. 

14. The mind of man adapted to the study of nature. 

15. Distinction between the physical sciences. 

16. Defini ion of Chemistry. 

17. Foundations of chemical science. Definition of the terms obser¬ 
vation, experiment and analogy. 




INTRODUCTORY. 


15 


on the mind ; by experiment , new facts are brought to light; by 
analogy , we infer what is unknown from what is known. Thus, 
suppose a person to notice that when a certain vegetable sub¬ 
stance, which is common in brooks and ponds and grows under 
water, is exposed to the sun, globules of air appear on its fila¬ 
ments, while no such globules of air are seen upon the weeds 
which are in shade. This is an observation. But it does not 
show the nature of the air which collects on the plant. The 
observer, by inverting over it a wine glass filled with water, sees 
the air rising up through the water while the water descends until 
the air fills the glass. He hayiow secured a portion of the air, 
and is ready to try an exp^i^^upon its nature. On introducing 
a burning taper into it, he findlohat the taper burns with greater 
brilliancy and fierceness than in common air. He has now as¬ 
certained that this air differs from the common air, in, at least, 
one property ; and hernext, is led by analogy to inquire, whether 
other green vegetables will not, in similar circumstances, produce 
an air that will support flame in a greater degree than common 
air. Thus we may suppose oxygen gas, might have been ob¬ 
served, experimented upon, and finally found to exist in a great 
variety of substances. 

18. All the knowledge we possess of external objects is found¬ 
ed upon experience ; this furnishes facts, and the comparison of 
these facts establishes relations. Such inductions, connected 
with the intuitive belief that the same causes will produce the 
same effects, lead to the knowledge of general laws , and these 
laws constitute a science. Thus has Chemistry beginning with 
scattered and isolated facts, advanced to its present distinguished 
rank among the sciences. 

Properties of Matter. 

19. The properties of matter are either Physical or Chemical; 
the former are considered in Natural Philosophy, the latter in 
Chemistry. 

20. The chemical properties of matter it is our object in the 
present course of study to investigate. The attraction of gravity 
which in physics, acts upon masses, has no influence in chemi¬ 
cal action ; but, in its place is found another species of attraction, 
called affinity, which operates only between the minute particles 
of matter. Heat, Light and Electricity have important influen- 

18. Process in the discovery of general laws. 

19. Properties of matter considered in Natural Philosophy and 
Chemistry. 

20. Chemical Properties of matter, and chemical agents. 



16 


INTRODUCTORY. 


ces upon chemical combinations ; We shall, therefore, consider 
these agents, before proceeding to the elementary substances of 
which all bodies are composed, and into which, by means of 
chemical analysis, all may may be resolved or separated. 

21. Heat , Light and Electricity are called imponderable agents , 
because they are not known to possess weight; We shall next 
proceed to the consideration of these imponderables. We shall 
then be prepared to consider the chemical elements of ponderable 
matter ; or Inorganic Chemistry . 

We shall next examine the chemical constitution of vegetable 
and animal substances ; the stud^^f which constitutes Organic 
Chemistry . 


21. Division of subjects. 



PART I. 


IMPONDERABLES. 
LECTURE II. 


GENERAL REMARKS ON THE IMPONDERABLES.—HEAT.—EXPANSION 
BY HEAT.—THERMOMETERS. 

22. There are certain agents, called imponderable , of which the 
nature is unknown, and which have a very important influence 
over all terrestrial matter. These are Heat or Caloric , Light and 
Electricity , which last includes Galvanism. 

23. It is a question not yet decided, whether these agents are 
strictly material substances, or only motions*or affections of mat¬ 
ter. We cannot confine and exhibit them as we can other ma¬ 
terial bodies, nor do the most delicate balances show that they 
possess weight. For the latter reason, they are called imponder¬ 
ables. It is thought by some, that since we cannot show these 
agents to possess the common properties of matter, they ought 
not to be regarded as material existences. Some philosophers 
are of opinion, that they are not matter, but are the effect of vi¬ 
bratory and rotatory motions among the particles of matter ; and 
that their intensity depends on the velocity of their motions. 

But whether they be material existences, or only properties of 
matter, they are found to be subjected to physical laws. We shall, 
therefore, consider them as invisible fluids pervading all nature, 
and requiring only the intervention of other kinds of matter to 
render them evident. 


HEAT AND CALORIC. 

24. Heat , in common language, is used to signify both cause 
and effect. In science, where great precision is necessary* 
terms must be carefully defined. By caloric * Chemists under¬ 
stand the cause of which heat is the effect ; it is the agent which 
produces in our minds, by means of external organs, the sensa- 

* From calor , a Latin word signifying heat. 

22. Imponderable agents. 

23. Different opinions with respect to the imponderable agents. 

24. Definition of caloric. 



IS 


IMPONDERABLES. 


tion of heat. The term igneous fluid , matter of heat , &c., mean 
the same as caloric. 

25. Considered as a material substance, caloric is a subtle, in¬ 
visible fluid, universally diffused and highly elastic, that is, com¬ 
posed of particles that strongly repel each other, but possessing 
an attraction or affinity for all other substances. 

26. There are six sources of caloric, viz. 1. tfye Sun : 2. Com¬ 
bustion : 3. Electricity: A. The bodies of living animals : 5. Chemi¬ 
cal action: 6. Mechanical action. The mechanical means of 
producing heat are friction and percussion. The rubbing together 
of two pieces of wood is an example of friction, and the hammer¬ 
ing a piece of metal, of percussion. By these means, wood and 
other combustibles may be set on fire : and many serious accidents 
have occurred in consequence, as the burning of factories, explo¬ 
sion of powder mills, and the like. 

27. Caloric is capable of two modes of existence ; in the one, 
it is manifested to the senses, and its degrees of intensity may be 
measured by means of certain instruments. When in this state, 
it is called free caloric , sensible heat , caloric of temperature , &c. 
In the second case, the caloric is concealed from the senses, and 
is said to be latent or hidden. 

Expansion. 

28. One of the most important and universal effects of caloric 
is, to expand all bodies into which it enters ; and that such is the 
effect of caloric is proved by the fact, that a body so expanded 
returns to its original bulk on cooling. 

Experiment. Let a small bar or cylinder of iron, a, be fitted 

to pass through the 
Fig. 1. aperture at b and let 

its length be such 
that it will fit into 
the notch c. On be¬ 
ing heated, it will be 
found too large too pass through the aperture at ft, and too long 
for the space c ; when cooled it will contract to its original di¬ 
mensions. 

29. A very useful application of this principle is familiar to 


25. Nature of caloric. 

26. Sources of caloric. Mechanical means of producing heat. 

27. Free and latent heat. 

28. Caloric expands bodies. Experiment to show the expansion of a 
solid body by caloric. 

29. Application of this principle in the manufacture of carriage 
wheels. 






HEAT. 


19 


wheel wrights. It is highly important that the parts of a car¬ 
riage wheel should be united in the firmest possible manner. 
For this purpose, when the wooden portions have been nicely 
joined, the iron band is constructed so small, that it cannot be 
forced on when cold. The band now being made red hot, it 
expands, so as readily, to encompass the wheel; and in cooling, 
it contracts, compressing and binding the parts and joints to¬ 
gether with an immense force. 

30. It is supposed that caloric causes expansion, by insinuating 
itself between the particles of a substance, and by its elastic force, 
driving them to a greater distance from each other. Thus a 
heated body occupies greater space, and is of a less specific 
gravity than when cold. 

31. It might be inferred a priori ,* that the expansive effect of 
caloric would be opposed by the cohesive attraction of the parti¬ 
cles ; and accordingly we find cohesion and caloric, universally 
acting as antagonists to each other. 

It has been mentioned, (§ 30,) that bodies exist in the solid, 
liquid or gaseous state, according to the prevalence of the co¬ 
hesive or repulsive forces. In solids, the power of cohesion, 
is greater than that of repulsion, and the particles are held 
closely together. In liquids, the cohesion is so far overcome, 
that the particles can move freely among themselves ; and in 
seriform bodies, though cohesion undoubtedly exists, it is not 
apparent, on account of the predominance of the repulsive power. 
We should hence expect, that liquids would expand more than 
solids and gases more than either, with the same addition of 
caloric, and this is practically true. 

32. It is demonstrable, that some bodies expand much more 
than others ; and that when any solid is heated gradually, through 
any range of temperature, the hotter it becomes, the more it ex¬ 
pands by the same acquisition of heat. For instance, if a metallic 
rod of known dimensions, be heated from 60° to 100° it will 
expand to a certain degree. If now another 40° of heat be ap¬ 
plied to it, the increase of its dimensions will be greater than in 
the former case. And this is easily explained ; for the cohesion 
being partially overcome by the first addition of heat, the second 

* By a priori is meant, beforehand, or prior to any reasoning or exper¬ 
imenting, on the subject. 

30. Manner in which caloric causes the expansion of bodies. 

31. Expansion opposed by cohesive attraction. Why liquids expand 
more than solids, and gases more than either. 

32. Expansion greater at certain stages of heat, with an equal increase 
of caloric, than at other stages. 




20 


IMPONDERABLES. 


portion will have less opposition to encounter and will produce 
a proportionally greater effect. 

33. By the application of heat, in various quantities, solid bod¬ 
ies may all, or nearly all be converted into liquids, as in the 
melting of ice, the fusion of wax, metals, &c. Liquids, by the 
further addition of caloric, may be converted into gases. 

34. An instrument called pyrometer , (measurer of fire, from 
the Greek, pur, fire, and metron , measure,) has been invented to 
show the degrees of intense heat, above those which we are able 
to estimate by the mercurial thermometer. Mercury boils and 
becomes vapor, at 660° ; above that point, therefore, it is inca¬ 
pable of measuring heat. The pyrometer depends for its opera¬ 
tion, on the expansion of metals, and shows the different degrees 
of expansibility of different kinds of metals. 

The figure shows a rod of metal, A A , resting horizontally 


Fig. 2. 



upon supporters. One end of the rod is fixed, the other end 
touches the wheel work, B B, which is so connected with the 
index C that a slight motion of the wheels, causes a considera¬ 
ble movement in the index. The rod of metal on being heated 
by the lamps 1, 2, 3, expands and presses against the wheel 
thus moved communicates motion to the index. The more 
expansible the metal is, the farther the index will move on 
the plate. 

35. The pendulum of a clock, in order to vibrate seconds, 

33. Effects of heat in changing the state of bodies. 

34. Pyrometer. Its use and construction. Describe the figure. 

35. Why will a clock go faster in winter than in summer ? How may 
this evil be remedied ? Why does a short pendulum vibrate faster than 
a long one ? 





































HEAT. 


21 


must*always be of a given length; but as metals expand with 
heat, the pendulum is liable to shorten in winter and lengthen in 
summer :—it follows that the clock will go faster in winter than 
in summer. By lengthening or shortening the pendulum, this 
evil may be remedied. About thirty-nine inches is found to be 
the length necessary for a pendulum to vibrate seconds. It may 
be readily understood why a short pendulum should vibrate 
faster than a long one, when it is 
considered that the pendulum is 
the radius of a circle, which circle 
is larger or smaller, according to 
the length of the radius. Thus 
suppose A and B to be two pen¬ 
dulums, of which B is the longer. 

B must describe the arc, c rf, of 
a circle, while A only describes 
the arc from e to /. 

36. Various circumstances have rendered it most convenient to con¬ 
struct pendulums of metal, though their liability to expansion and con¬ 
traction by change of temperature, is an imperfection. If the tempera¬ 
ture of the pendulum be raised, its dilatation will evidently remove its 
mass further from the point of suspension, and will cause its rate of 
vibration to be slower; while the diminution of temperature will be at¬ 
tended with the contrary effect. Thus it would follow, that with every 
change of weather the rate of the clock would vary. In like manner, 
the swinging motion which the balance wheel of a watch receives from 
the hair spring which impels it, depends on the distance of the metal form¬ 
ing the rim of the wheel from its center. 1/ this distance be increased 
the spring acts with less advantage on the mass of the wheel, and there¬ 
fore moves it more slowly ; and if it be diminished, for a similar reason, 
it moves more quickly. It follows, therefore, that when a wheel expands 
by increased temperature, the rate of vibration xvill be diminished ; and 
when it contracts by diminished temperature, the rate of vibration will 
be inci eased. A watch for the same reason, will fluctuate in its rate of 
keeping time with every change of temperature. Various ingenious in¬ 
ventions have been resorted to, to compensate for the irregularities, oc¬ 
casioned by increased or diminished temperature upon the metallic rod 
of the pendulum, or balance wheel of a watch. 

Expansion of Liquids. 

37. Liquids, like solids, differ greatly in their several expansi¬ 
bilities by heat. In general, the less the heat requisite to boil a 

35. Why will a clock go faster in winter than in summer ? How may 
this evil be remedied ? Why does a short pendulum vibrate faster than 
a long one ? 

36. Effect of expansion and contraction upon the balance-wheel of a 
watch. 

37. Liquids vary in their capacities of expansion by heat. Experi¬ 
ment to show the different effects of heat in the expansion of alcohol 
and water. General rule with respect to the expansion of liquids. 

3 






22 


HEAT. 


liquid, the more it will expand by a given increase of temper¬ 
ature. And further, liquids like solids are subject to an increas¬ 
ing rate of expansion, as the heat is raised higher. 

Experiment. Fill to 0 , 0 , 
two small matrasses,* of 
equal dimensions, the one 
with alchohol, the other 
with water; place under 
each, a pan'of burning char¬ 
coal. Both liquids will rise 
in the tubes; but the alcohol 
will stand considerably 
higher than the water. 

To render the liquids more 
plainly visible, they may be 
tinged with cochineal, or some 
other coloring matter. Instead 
of the burning charcoal, the 
same experiment may be tried 
by immersing the bulbs in a 
vessel of hot water. On being 
removed from the heat, the 
liquids will gradually return to 
their original bulk as they cool. 
As a general rule, those liquids 
expand the most uniformly 
through a steady rise of temperature, which require the strongest heat 
to make them boil. Alcohol boils wbth a lower degree of heat than 
water; it is, therefore, exceedingly expansive ; and the nearer it ap¬ 
proaches the boiling point, the more rapidly its volume increases. 

38. Since expansion by change of temperature changes the 
weight of a given bulk of a liquid, and this change of weight is 
in the inverse proportion to the expansion, it follows, that all the 
ordinary methods for determining the specific gravities of liquids 
may likewise be applied to determine their degree of expansion. 
The specific gravity of the same liquid at different temperatures 
is different, and always in an inverse proportion to the expansion : 
the less the specific gravity, the greater, in the same proportion, 
will be the expansion. 

39. The French Chemists have determined the absolute expansion of 
mercury by means of an apparatus here represented, and which may be 
applied in the same manner in the case of other liquids. It depends on 
the hydrostatical principle, that two vertical columns of liquid communi¬ 
cating by a horizontal tube, will have heights in the inverse proportion 
of their densities. 

* Chemical, bulbous, glass vessels. 

38. Manner of determining the degrees of the expansion of liquids. 

39. Describe the apparatus for determining the absolute expansion of 
mercury or other liquids. 


Fig. 4. 


















IMPONDERABLES. 


23 


Fig. 5. 



A T and A' T represent two vertical tubes of glass, which communi¬ 
cate with a horizontal tube T T. They are filled with mercury to the 
height n n. So long as the temperature of the mercury in this appara¬ 
tus is the same in every part, the surfaces of the mercury in the two 
vertical tubes must stand at the same level: but if the mercury in one 
tube, be reduced to the temperature of melting ice, and in the other be of 
a higher temperature, the expansion produced by the higher temperature, 
will cause the mercury in one tube to dilate in a greater degree than in 
the other, and to become specifically lighter; consequently, the higher 
column of mercury in the tube A' T will balance the lower column in 
the tube A T, at the lesser temperature. The highest of these columns 
will be in an inverse proportion to the specific gravity of the mercury. 
The heights, therefore, being accurately observed, the relative specific 
gravities will be known, and hence the expansion which takes place be¬ 
tween the two temperatures may be inferred. 

Exception to the general law of Expansion. 

40. To the general law of expansion by heat and contraction 
by cold, water furnishes a most remarkable exception. On cool¬ 
ing this fluid from any temperature down to 40 G , it will be found 
to^c on tract gradually like any other body ; but if the cooling be 
further continued, the contrary effect will take place, and the 
water will expand slowly till it reaches the temperature of 32°, 
when it becomes ice. Water therefore has its greatest density at 
40° and is consequently specifically heavier at that temperature, 
than at any other, either above, or below it. It is known that 
water in freezing, takes a regular crystaline form ; and it is sup 
posed that the particles commence arranging themselves in this 
form at 40°. Now it is quite possible, that in assuming this 
form, the particles may occupy more space, than in their ordina¬ 
ry relative positions ; and the supposition is supported by the 
facts, that solutions of salts, in crystalizing are enlarged in bulk, 

40. Effect of cooling water below 40°. Change which takes place at 
this temperature and probable cause of this change. 















24 


HEAT. 


and that several of the metals on solidifying after fusion, also ex¬ 
pand, taking, at the same time, a crystaline structure. Cast-iron, 
antimony and some other metals are known to possess this prop¬ 
erty, which renders them peculiarly fit for castings ; for, on 
cooling, they perfectly fill the mold ; whereas, if they followed 
the general law of condensing by the loss of heat, they would 
shrink, and receive an imperfect impression. 

41. This property of water has very important consequences ; 
as without it, ice being heavier than water would sink in it; 
new portions would successively freeze and sink, till the lakes, 
rivers, &c., were frozen to the bottom, destroying the animals 
which inhabit them, and permanently obstructing navigation. 

Fig. 6. Let a d represent two 

vessels filled with water at 
the temperature of about 
66°; b b' are tin trays sur¬ 
rounding the upper part of 
one vessel, and the under 
part of the other, and filled 
with a freezing mixture, 
viz., ice and salt. The 
first effect of the cold is to 
reduce the temperature of 
. . the whole mass of water 

to 40 , at which point as we have seen, water is at its greatest 
density. After this, the cooling process in the vessel a, will be 
limited to the surface, where the temperature will gradually fall 
to 32 , at which point the water will freeze ; for the freezing 
water, being lighter than the water below, will remain on the 
surface. This is what takes place in lakes and large bodies of 
water. 

In the vessel d, where the cold is applied at the bottom, the 
effect is very different; for the water when cooled below 40° 
becomes lighter and rises, the warmer or heavier portions de¬ 
scend, in their turn become cooled, and again rise ; other, suc¬ 
cessive portions follow the same course, until the whole, being 
reduced to 32°, or the freezing point, hardens into one solid body 
of ice. The process described in the vessel a, or where the cold 
is at the surface, is that which goes on in nature ; that in the 
vessel d, is what would take place, did not water, unlike all 
other known substances, become lighter before it freezes, so that 
a stratum of ice-cold water at 32®, lies over a mass of warmer 



41. What would be the effect of cold on lakes and rivers if water 
became heavier as it changed to ice ? 












IMPONDERABLES. 


25 


water at 40°. It appears a wonderful provision of the Almighty, 
that, for the convenience and preservation of men and animals, 
water should be almost the only substance which does not con¬ 
tinue to become heavier as it grows colder. 

43. The force with which water expands in freezing is im¬ 
mense, bursting not only earthen and glass vessels, but even 
cannon and strong metallic vessels, and causing chasms in rocks. 

Expansion of Aeriform Bodies. 

44. In their expansion by heat, aeriform bodies differ from 
liquids and solids in three important points:— 

1st. Aeriform bodies expand more than liquids and solids with 
the same increase of temperature ; the cohesion of their particles 
being already more than counterbalanced. 

2nd. They expand equally. 

3d. They expand uniformly through all temperatures. 

45. Experiment 1st. Hold, near the fire, a bladder partially 
inflated. The air within, being expanded by the heat, will soon 
distend the bladder. 

Experimented. Place an emp¬ 
ty thermometer tube with its open Fig. 7. 

end in a glass of water, and apply 
the hand to the bulb a ; the heat of 
the hand will cause the air within 
the bulb to expand so that a portion 
will rush out and rise in bubbles 
through the water; on removing 
the hand from the ball, the water 
will rise in the tube to fill the va¬ 
cuum caused by the condensation 
of the air. 


43. Expansive force of freezing water. 

44. Particulars in which aeriform bodies differ from liquids and solids 
in their expansion by heat. 45, Experiment 1st. 

3* 











26 


HEAT. 


Thermometers. 

46. The senses being very fallible means of measuring heat, 
the wants of science urgently demanded the invention of some 
instrument for that purpose. About the middle of the seven¬ 
teenth century, the Florentine Academicians invented such an 
instrument. It consisted of a glass tube, with a bulb blown at 
one extremity, then filled to a certain mark with alcohol, and 
closed at the open end ; the expansion of this liquid, or its rise 
above the mark, indicated heat ; and its contraction, or fall below 
the mark, indicated.coM. This instrument, called the Florentine 
glass , was introduced into England by Boyle. At first, the sup¬ 
position that a liquid could contract and expand in a tube closed 
at both ends, was ridiculed as absurd, and it was not until the 
philosophers of the day were convinced by the experiments of 
Boyle, that this fact was admitted. 

47. The invention of the first thermometer,* is usually as¬ 
cribed to Sanctorius, an Italian; this instrument depended for its 
effects on the expansion of air by means 
of heat. If a matrass be held in both 
hands by its bulb, the warmth com¬ 
municated will expand the air within, 
and expel a portion of it. Now im¬ 
merse the mouth of the instrument 
in a vessel containing a colored liquid, 

(See fig. 8.) and remove the hands ; 
the air will gradually cool and contract, 
while the liquid will rise into the tube, 
to supply the place of the air which 
was forced out. The apparatus in this 
condition, constitutes the Air Ther¬ 
mometer of Sanctorius. On the ap¬ 
proach of a heated body to the bulb, the 
expansion of the enclosed air drives 
down the liquid in the tube ; thus, the 
lower the column of liquid, the greater 
is the degree of heat indicated ; this is 
the reverse of what takes place in the 

* From the Greek therme heat, and metron measure, meaning an In¬ 
strument to measure the degrees of heat. 


46. Why was the invention of the thermometer important? First 
attempt towards the construction of the thermometer. 47. Thermometer 
of Sanctorius. What causes the liquid to descend in the tube on the ap¬ 
proach of a heated body while in the mercurial thermometer, the column 
of mercury rises under the same circumstances ? 


Fig. 8. 











IMPONDERABLES. 


27 


common mercurial thermometer, where the greater the height 
of the column of mercury, the greater is the degree of heat signi¬ 
fied. 

The superior advantages of the air thermometer, consist in 
the great amount of expansion of air by which minute changes 
of temperature are rendered obvious, and the uniform increase 
of bulk of air, on account of which this thermometer is equally 
accurate, in high and low temperatures. But these advantages 
are outweighed by the objections, that so great an expansion 
would require an unmanageable length of tube for observing any 
considerable increase of heat, and that the variable pressure of 
the atmosphere influences air independently of temperature. 

48. A modification of the air thermometer, invented 160 years 
ago, by Sturmius, and revived by Prof. Leslie, in 1804, is ex¬ 
tremely useful'in some experiments. 

It consists of a glass tube, bent like 
the letter U, and having a bulb, a 
and bj at each extremity. It con¬ 
tains a colored liquid, commonly 
sulphuric acid, tinged with cochineal. 

If heat be applied to one of the 
bulbs, as at «, it will expand the air 
within, -causing the descent of the 
liquid in one branch, and its ascent 
in the other towards b. The distance 
the liquid moves is measured by a 
scale attached to one of the branches, 
and divided into equal parts, called 
degrees. It is obvious that, with 
this instrument, we can only learn 
the difference of the temperature of_ 
the two bulbs. On this account, it^ 
is called the Differential Thermometer. 

49. HowarcPs Differential Thermometer , is very delicate. In 
form and principle, it resembles that of Leslie ; but the fluid it 
contains, is sulphuric ether , an extremely volatile substance. One 
of the bulbs is left with a minute opening, and a sufficient 
quantity of the colored ether being introduced, it is then boiled. 
The vapor of ether now rises and fills the tube, expelling the aip 
through the aperture. While the ebullition is going on, and the 
tube is full of vapor, the opening is suddenly closed by fusing the 
glass.* The etherial vapor now indicates the changes of tempera- 

* Glass tubes thus closed, are said to be hermetically sealed. 




48. Leslie’s Differential thermometer, 

49. Howard’s Differential thermometer. 












28 


HEAT. 


ture, as the air does in the themometer of Leslie, but as the vapor 
expands in one branch, it causes a pressure on that in the other, 
and the latter becomes liquid thus relieving the countervailing 
pressure which would impede the motion of the ether, if the 
second bulb contained an incondensible gas or vapor. 

50. As air is not extensively applicable for the purpose of a 
thermometer, and as the small expansibility of solids render them 
almost useless for this purpose, Chemists have sought among 
liquids for one, combining the most advantages with the fewest 
objections. It is evident that perfect fluidity and freedom of 
motion are essential; oils and viscid liquids, therefore, are unfit, 
though a thermometer of the former was recommended by 
Newton. To be of extensive application, also, the liquid should 
be one which boils with great difficulty ; for its indication can be 
taken only while it retains the liquid state ; and, for the same 
reason, it should be able to support a great degree of cold with¬ 
out freezing. Its expansion, also, should be as nearly as possible 
uniform, through a great range of temperature. Mercury or 
quicksilver, though far from perfect, possesses these requisites in 
a higher degree than any other liquid with which we are ac¬ 
quainted. It is, accordingly, in general use as a thermometer. 

51. The principal scales in use, are 1st. The centigrade, or 

that of Celsius, used principally in France and Sweden, and 
generally known over Europe. Of this scale the freezing point 
is marked 0°, and the boiling point 100°. 2nd. The scale of 
Reaumur, used in France before the revolution, and still retained 
in Spain, on which the freezing point is at 0®, and the boiling 
point at 80®. 3d. That of De Lisle, the use of which is confined 

to Russia ; this is a descending scale, the boiling point being 0° 
and the freezing point 150®. 4th. The scale of Fahrenheit 
which is used in this country, Great Britain, and Holland. On 
this the freezing point is marked 32®, and the boiling point 212°, 
the intermediate spaces containing 180 equal parts or degrees. 

52. A temperature expressed in degrees of one of the above 
scales is easily convertible to those of another, by applying the 
following rules. 

1st. To reduce any number of degrees of the centrigrade scale to terms 
of Fahrenheit, multiply the number by 9, divide by 5, and to the quotient 


50. Objections to air and solids for extensive use as thermometers. 
Why oil is unfit. Requisites in a liquid to be used for this purpose. 

51. Different thermometer scales in use, 

52. Rule for reducing degrees of the centigrade thermometer to those 
of Fahrenheit, and for converting degrees of Fahrenheit to those of the 
Centigrade. Examples. Rule for reducing degrees of Reaumur’s 
thermometer, to Fahrenheit’s and for converting degrees of Fahrenheit 
to those of Reaumur. Examples. 



IMPONDERABLES. 


29 


add 32. The converse process is as follows ; snbstract32 from any num¬ 
ber of Fahrenheit’s degrees, multiply the remainder by 5, and divide by 
9; the quotient will express, the same temperature in degrees of tlio 
centigrade. 

Examples. 


Centigrade. Fahrenheit. 

100°X 9=900=5=180 add 32=212°. 

Fahrenheit. Centigrade. 

212°—32=180 X 5=900=9=100° 

2d. The degree of Fahrenheit being in length to 
that of Reaumur in the ratio of 4 to 9 ; to reduce an 
expression of Reaumur’s scale to one of Fahrenheit, 
we must multiply by 9, divide by 4 and add 32; and, 
on the contrary, to obtain an expression by Reau¬ 
mur’s scale equivalent to a given one by Fahren¬ 
heit’s, we substract 32,multiply by 4 and divide by 9. 


Example . 

Reaumur. Fahrenheit. 

16X9=144-7-4=36° add 32°=68°. 
80°X 9=720=4=180° add 32°=212°. 


Fahrenheit. Reaumur. 

212°—32=180 X 4=720-7-9=80°. 

68°—32=36X 4=144=9=16°. 

Thermometers are sometimes constructed with 
different scales affixed to the same tube, so that tho 
correspondence of the degrees of different thermom¬ 
eters may be at once perceived. The figure repre¬ 
sents a thermometer, with Fahrenheit’s and Reau¬ 
mur’s scales. 

53. The mercurial thermometer is accu¬ 
rate in its indications of temperature, as high 
as 212° ; for, though mercury, like other li¬ 
quids, expands proportionally more at high 
than at low temperatures, the irregularity is 
exactly compensated by the expansion of the 
glass tubes. But above 212°, the glass ex¬ 
pands more rapidly than the mercury, and 
the indications are less accurate. This in¬ 
strument may, however, be used for common 
purposes, to compare degrees of heat as high 
as 500°, and it is quite accurate as low as 39° 
below zero, when it freezes. When it is de¬ 
sirable to measure temperatures lower than 39°, 
alcohol must be employed. 


Fig. 10. 



63. Irregularities of the mercurial thermometer. 





















































30 


HEAT. 


LECTURE III. 

CONDUCTION OF HEAT.—RADIATION AND REFLECTION .—LATENT 
HEAT.—LIQUEFACTION.—FRIGORIFIC - MIXTURES. 

Conduction of Caloric or Heat. 

54. A piece of. wood may be held in the hand by one end, 
while the other is burning ; but if a bar of iron be heated at one 
extremity, the other will soon be too hot for the hand. This 
difference arises from the unequal facility with which bodies al¬ 
low the passage of caloric through their masses ; or, in other 
words, from the unequal conducting powers of bodies. 

When a solid is heated, the caloric is received by the par¬ 
ticles nearest the source of heat, and transmitted to the mole¬ 
cules next them, and sq on till it is diffused through the whole 
mass. 

55. Of all known bodies, metals transmit caloric the most 
rapidly ; they are, therefore, called the best conductors. 

Experiment. Take four small rods ; one of metal, one of 
glass, one of wood, and one of whale-bone, and cement one 
end of each to a lump of sealing-wax ; then successively ex¬ 
pose each rod at the opposite end to the heat of a blow-pipe. 
The metal soon becomes so hot as to melt the sealing-wax and 
fall from it: but the wood and whale-bone, may be destroyed 
by the heat, and the glass so heated, that it may be bent, while 
the sealing-wax at the opposite end has not become heated suffi¬ 
ciently to melt it. 

56. Not only do bodies of different kinds possess different 
conducting powers, but bodies of the same class, vary in this 
respect. 

Experiment 1st. Thus, if equal rods of several metals be 
coated with wax, at one extremity, and be equally exposed ta 
heat at the other, the wax will melt upon some of the rods much 
sooner than upon others. 

54. Difference in the power of wood and iron to conduct heat. Man¬ 
ner in which caloric is transmitted in solid bodies. 

55. Best conductors of caloric. Experiment to show the different 
conducting power of metal, glass, wood, and whale-bone. 

56. Metals vary in their conducting powers. Experiment 1st. Ex¬ 
periment 2nd. Arrangement of metals according to their conducting 
powers. 



IMPONDERABLES. 


31 


Experiment 2nd. Let cones of different kinds of metals be sev¬ 
erally tipped with wax, and placed upon a heated metallic plate, 
the wax will first melt upon the one which is the best conduc¬ 
tor of heat, and so on, thus, showing the relative conducting 
powers of the different metals composing the cones. 

By some recent experiments, the conducting 
Fig. 11. power, of several metals has been found to decrease 
in the following order, viz., gold, silver, copper, 

A platinum, iron, zink, tin and lead. 

57. Among bad conductors of heat are stones, 

_ MPt dry wood, charcoal, dry air, feathers, and other 

light animal and vegetable substances, particular¬ 
ly the usual materials for clothing. It is on account of the 
small conducting power of wool, cotton, &c. (in connection 
with the facility of manufacturing them,) that they are chosen 
for their particular use ; for in summer, when the solar heat 
would scorch the skin, they impede its progress to the body, and 
in winter they retard the passage of heat from the body to the 
cold air. Wool is not so good a conductor as linen ; in a hot 
summer’s sun, therefore, a light, white woolen dress is preferable 
to linen. Owing to the difference of their conducting powers, 
the different articles in a room, though really at the same tempera¬ 
ture, will seem different to the touch. A marble slab will feel 
colder than a woolen carpet, because it absorbes heat from the 
hand more readily. For the same reason good conductors, when 
heated, transfer their caloric rapidly to the hand, and will there¬ 
fore burn it, though a bad conductor, at the same temperature 
will scarcely feel warm. Thus coffee pots and other metallic 
vessels, intended to hold hot liquids have wobden handles. The 
conducting power of metallic vessels gives them an advantage 
over glass or earthen ware for heating liquids rapidly. 

58. The low conducting power of charcoal has given rise to a useful 
application of it in the Refrigerator* There are different kinds of this 
article ; a simple and useful one may he made as follows ;—procure a box 
of wood, divided by partitions of tin and iron, into three compartments. 
Inclose this box in one larger, by about an inch in each of its internal 
dimensions. The space between the boxes is' to be filled with powdered 
charcoal. If meat, butter, wine, or other articles, be put into the two 
extreme compartments, and ice into the middle one, they may be pre¬ 
served cool and fresh in the hottest weather; for the charcoal scarcely 

* The term is from the Latin, and signifies a cooler. 

57. Bad conductors. Why wool, cotton &c., are used for clothing. 
Why articles in the same room appear of unequal temperature. Why 
wooden handles are used for metallic coffee pots. Why metallic vessels 
are better than earthern for heating liquids. 

68. The refrigerator. Ice houses. 






82 


HEAT. 


permits the passage of caloric from without, while it is readily transferred 
through the metallic partitions from the meat &c. to the ice. “A great 
saving is also effected in this way in the consumption of ice. In con¬ 
structing ice houses, straw, which is an imperfect conductor of heat, is 
usually placed around the walls, roof and floor. A building made with 
double walls, having a space between them filled with air furnishes an 
excellent ice house ; for air where no source of radiation is present, is 
nearly impenetrable by heat. 

Conducting Power of Liquids. 

59. Hitherto' we have remarked on the conducting power of 
solids. Liquids possess the power of conducting heat in a very 
small degree. Heat applied to one proportion of a liquid is 
distributed through the mass, not by conduction, as in the case 
of solids, but by the motion of the particles. When we heat the 
bottom of a vessel containing a liquid, the particles nearest the 
source of heat become warm, expand, and being then lighter 
than the rest, rise to the upper surface ; the .next stratum does 
the same, and so on till the whole is heated. But if the heat be 
applied at top, the caloric will penetrate but a small distance 
downward. 

\ \ ' 

60. Experiment ls£. Let a 
be a glass vessel nearly filled 
with water, and including an 
inverted air thermometer; b 
is a small dish containing burn¬ 
ing charcoal, and separated 
from the thermometer bulb by 
a thin stratum of water. While 
the surface of the water is 
heated to the boiling point, the 
thermometer below' will indi¬ 
cate very little increase of 
temperature. 


59. Mode in which heat is distributed through liquids. Why liquids 
do not become heated when caloric is applied to the upper surface. 

60. Experiment 1st. . 


Fig. 12. 



















IMPONDERABLES. 


33 


Fig. 13. 



61. Experiment 2nd. Let a and b represent two thin glass 
tubes filled with water. If the heat of a lamp be applied to the 
bottom of the tube a, the whole mass of water within the tube 
will soon become equally heated and begin to boil. But let the 
heat be applied near the top of the tube b , and the surface of 
the water may be made to boil while the water at the bottom 
remains cold. Hot water being lighter than cold, it will remain 
at the surface ; or, if the particles are heated at the bottom, 
they will rise by their specific levity, and the cold ones will 
descend to fill the vacuum. 

62. Experiment 3d. Fill a glass vessel with water and throw 
Fig. 14. into it a few particles of amber, or any other substance 

of nearly the same specific gravity as water ; then apply 
the heat to the bottom of the vessel, and a rising current 
will immediately begin in the center of the vessel, and de¬ 
scending currents at its sides as represented by the direc¬ 
tion of the arrows. It is by successive changes in the weight 
of the different particles of water, that the whole mass is 
heated. The caloric,by enlarging the bulk of a particle, ren¬ 
ders it specifically lighter than portions of the water not heat¬ 
ed ; and it is a law of fluids, that the lighter portions rise 
above the heavier. Thus the ascending and descending 
currents will continue till the whole mass of water is 
heated to the boiling point. 

63. Oil is a bad conductor of heat. 

61. Experiment 2nd. 

62. Experiment 3d. 

63. Experiment to show that oil is a bad conductor. Why soft solids, 
like puddings, &c. cool more slowly than liquids. 

4 










34 


HEAT. 


Experiment. Let a b represent a thin glass tube, about two 

feet in length, closed at one end, 
and open at the other ; pour into 
it about two inches of powdered 
ice or snow, then upon this mass 
pour about eight inches of oil c ; 
and over this two or three inches 
of alchohol d. The alchohol 
may now be boiled, and even 
evaporated by the flame of a 
lamp, while the oil will not be 
sensibly heated, nor the frozen 
mass melted. As liquids are 
heated by reason of internal mo¬ 
tion, they must become cool in the same manner : and hence we 
see why soft solids and semifluids, like puddings, &c. cool very 
slowly : their intestine movements being prevented or impeded, 
while the conducting power is very small. 

Conducting Power of Aeriform Bodies. 

64. It has never been settled whether aeriform bodies possess 
any power of conducting heat; if they do, it is in a very slight 
degree. This class of substances is heated precisely as liquids 
are, viz., by internal movements among their particles. 

65. When air is heated,currents are produced. In a room, where 
there is a fire, the air in the upper part is warmer than that in 
the lower, because the warm air being lighter ascends; after part¬ 
ing with caloric, it descends, and thus in a warm room there is 
always an ascending and descending current of air. If the door 
of a warm room be opened, warm air rushes out at the upper 
part, while cold air enters below. This may be proved, by hold¬ 
ing the flame of a lamp at an open door : at the upper part, the 
flame will be blown outwardly, at the lower part inwardly, while 
midway, the flame will remain in its usual perpendicular posi¬ 
tion. 

66. Argand lamps , or those which have a circular hollow wick 
surrounded Avith a glass cylinder, are supplied Avith a current of 
fresh air to support combustion by the same principle as the 
draft of a fire place. The heat of the flame expands the air 
above it, and this being thus rendered lighter than the atmos¬ 
phere around, rises and leaves a vacuum toAvards which the sur¬ 
rounding portions of air now press. The glass chimney becoming 

64. Aeriform bodies are heated in the same manner as liquids. 

65. What produces currents of air. 

66. Argand lamps. 


Fig. 15. 


a 









IMPONDERABLES. 


35 


heated, serves still more to rarefy the enclosed air, and by 
thus rendering the upward current more lively, promotes com¬ 
bustion ; for with new portions of air, to supply the place of that 
which has ascended, fresh quantities of oxygen are added, and 
the flame is increased. 

67. When a fire is made in the open air, winds from all quar¬ 
ters are rushing towards it, even in the calmest day. This is 
because the air near the fire, being made lighter by heat, rises 
into higher regions of the atmosphere, and colder air rushes in 
to fill the vacuum. 

68. The ventilation of rooms designed for large assemblies is 
effected by means of a dome, having an aperture at its vertex, 
under which is suspended a chandelier to heat the air and cause 
a draught. The cold air being constantly admitted below, to 
supply the place of the heated and, vitiated air which ascends, a 
free current is kept up. 

Radiation and reflection of Caloric or Heat. 

69. All bodies are constantly giving out caloric ; and the tem¬ 
perature of a body rises when it receives more than it gives out, 
or falls when it gives out more than it receives. The calorie 
thus given out, is called radiant caloric , and following the same 
law as light proceeding from a luminous body, it emanates equal-' 
ly from all sides of the heated body, and proceeds in straight lines 
moving with great velocity. By suspending a heated ball, and 
holding the hand at a short distance from it on any side, (except 
above it, where heated currents of air would be felt,) the heat 
will be immediately perceived, and in the same degree in all di¬ 
rections. In this case caloric is radiated as it is from the Sun, 
the great fountain of heat. 

70. Radiant caloric is reflected by all bodies ; and the laws 
which govern this reflection are the same as those which gov¬ 
ern the reflection of light. 

71. When a ray of heat falls obliquely upon a surface whether 
plane or curved, its direction is altered ; and the divergence is 
such, that, if we draw a perpendicular to the surface through 
the point where the ray strikes it, the angle between this perpen¬ 
dicular and the incident ray, is precisely equal to that between 
the same perpendicular and the reflected ray : in other words, 
the angle of incidence is equal to the angle of reflection. The re¬ 
flection of heat is easily proved by experiment; 

67. Why wind blows towards a fire made in the open air. 

68. Ventilation of public rooms. 

69. Radiant caloric. 

70. Reflection of radiant caloric. 

71. Law which governs the reflection of heat. 




36 


HEAT. 


72. Experiment 1st. Resting one edge of a sheet of tin upon 
the hearth, incline it backward, till, on holding your face verti¬ 
cally over it, the image of the fire can be seen in the tin ; the 
warmth will be felt-upon the face, though it be screened from 
the direct heat of the fire. 


Fig. 16. 



73. Experiment 2nd. Place a heated iron ball in the focus of a 
concave metallic mirror ; opposite to this, and at any convenient 
distance, place a second concave mirror, in the focus of which 
put a candle having on its wick a bit of phosphorus. The di- 
verging rays of radiant caloric proceeding from the ball to the 
mirror a, 'are reflected by it in parallel lines to the mirror b which 
converges them at its focus, igniting the phosphorus and thus 
lighting the candle. If a thermometer be substituted for the 
candle, the. mercury in it will rise. 

74. Experiment 3d. Remove the heated ball from the focus of 
the mirror a (fig. 16,) and replace it by a piece of ice ; a ther¬ 
mometer in the focus of the mirror b y now radiates more caloric 
than it receives, and the mercury will instantly fall. 

This experiment has given rise to a supposition that a fluid of 
cold existed, and was radiated by the ice ; an hypothesis now 
exploded, because it is unsupported by fact, and unnecessary to 
explain any phenomena. Cold is merely the absence of heat’; 
of absolute cold we have not, nor does it appear that we can 
have any notion. 

75 Experiment 4th. Sir Humphrey Davy contrived the fol- 


72. Experiment 1st. to prove the reflection of heat. 

73. Experiment 2nd. 

74. Experiment 3d. 

75. Experiment 4th. 












IMPONDERABLES. 


37 


Fig. 17. 



lowing mode of showing the radiation 
of caloric. He placed the mirrors ver¬ 
tically, (as in the figure,) with a wire 
basket of burning charcoal in the focus 
of the upper mirror, and a little dish of 
phosphorus in the lower one. The 
phosphorus will be set on fire by the 
reflected heat from the lower mirror. 
Now all the heat that reaches this mir¬ 
ror, and is concentrated in its focus, 
must be radiant and reflected ; for the 
current of heated air passes upwards. 

76. Bodies vary in their powers of 
radiating, and of reflecting caloric ; and 
these two properties are in an inverse 
proportion to each other ; that is, those 
substances which are the best radiators , 
a re, generally, the worst reflectors : or as the radiating power in¬ 
creases, the reflecting power diminishes. 

Polished surfaces reflect caloric better than rough ones ; and 
the reflecting power of the same surface is directly in proportion 
to its degree of polish. Of all bodies, the metals when polished, 
are the best reflectors ; hence, they are used for mirrors, and for 
vessels to contain hot liquids as tea, coffee, &c. The heat which 
would be radiated from an earthen, or an unpolished vessel, is 
reflected back by a polished metal to the liquid ; hence, also the 
reason why polished andirons, &c. continue cool though ex¬ 
posed to the fire. Some of the metals are much better reflect¬ 
ors than others ; and some alloys, or compounds of different 
metals, are better than pure metals : brass, an alloy of copper 
and zinc, is an excellent reflector. 

77. It is obvious that reflection must be directly opposed to 
absorption ; and since it is equally obvious that the more caloric 
a body has absorbed, the more it will radiate, the reason is man¬ 
ifest why the best reflectors are the worst radiators. 

76. Reflection and radiation opposite qualities. Examples: the met¬ 
als. 

77. Why are the best reflectors, the worst radiators. 

4* 














3S 


HEAT. 


Fig. 18. 



78. The differential thermometer is found to be very useful in 
experiments upon radiant heat; as, when one of the bulbs is ex¬ 
posed to a higher temperature than the other, the difference be¬ 
tween them is instantly shown, by the falling of the colored fluid 
below that which is most heated. 

Experiment 1st. Suppose a highly polished metallic mirror, a, 
placed a few feet from a cubical tin vessel filled with boiling 
w r ater ; let a differential thermometer be placed so that one of 
the bulbs shall be in the focus of the mirror, and an instantane¬ 
ous rise of the temperature will be indicated by the instrument. 
If a glass mirror be substituted for the metallic one, the ther¬ 
mometer will be much less affected, by which it appears that 
glass is not so good a reflector of heat as polished metal. If the 
surface of the reflector be coated with lamp-black, all reflection 
is destroyed, and of course the thermometer is not affected. If 
a screen c, be interposed between the tin vessel of hot water and 
the thermometer, the latter will immediately indicate the ab¬ 
sence of a portion of heat it before received, though the source 
of the heat is as near the bulb as before ; this shows that the 
thermometer was not affected merely by contiguity to the heated 
body, but by radiated heat. 

78. Use of the differential thermometer in experiment upon radiant 
heat. Suppose a glass mirror be substituted for the metallic one, or the 
thermometer coated with lamp-black. How is it proved that the ther» 
mometer was not affected by contiguity to the heated body ? 

































IMPONDERABLES. 


39 


79. Experiment 2nd . If a cubical tin vessel, having one of 
its sides coated with lamp-black, another papered, and another 
glazed, be filled with boiling water, and the thermometer placed 
in the focus of a metallic reflector, it will be found, that as the 
different sides are respectively presented to the reflector, the 
thermometer will exhibit different degrees of temperature, show¬ 
ing that the different sides of the vessel possess the power of ra¬ 
diating heat in different degrees. 

The radiating power of lamp-black is found to be 100° 


98° 


paper, 
glass, 
bright tin, 


90° 

12 ° 


80. Those bodies which absorb heat most readily , radiate it 
most powerfully, that is absorbing and radiating powers are 
equal; a piece of iron heats soon, and parts with its heat readi¬ 
ly ; a brick neither heats as soon, nor so quickly parts with ca¬ 
loric. 

It was formerly supposed that such substances as received heat most 
readily, must retain it longest; philosophers, therefore, thought that 
housekeepers should make their tea in earthen or porcelain tea-pots, 
rather than in metallic ones; but tea-makers insisted that they found by 
experience , that tea would “ draw best ” in bright silver or pewter tea¬ 
pots. The latter opinion is now proved by philosophy to be correct, 
since water retains its heat much longer in the polished metallic vessel, 
and, by this means extracts more fully the peculiar virtues of the tea- 
leaves. 

81. Some colors absorb caloric more readily than others. This may 
be shown by a very simple experiment. Take a piece of black and an¬ 
other of white woollen cloth, and lay them upon the snow, when the 
sun is shining. In a few hours the black will be found to have sunk 
considerably below the surface of the snow, while the white will remain 
on the surface. From this we infer, that the black cloth absorbed caloric 
from the sun, and gave it off in sufficient quantity to melt the snow be¬ 
neath, while the white did not absorb, and consequently did not give off 
caloric ; with respect to light, black bodies absorb all the rays and re¬ 
flect none ; while, in the case of caloric, black bodies not only absorb, 
but reflect in an equal proportion. Thus a white beaver hat is cooler 
for the head, in summer, than a black one, and light colored garments 
are more agreeable than dark colored. 

82. We have now considered two modes in which a hot body 


79. Experiment 2nd. Illustrating by means of the differential thermom¬ 
eter the radiating powers of lamp-black, paper, glass and tin. 

80. Absorption, and radiation equal. Why metallic tea-pots are better 
than earthen. 

81. Different powers of colors to absorb caloric. 

82. Two modes in which bodies lose caloric. Heat of the atmosphere, 
how produced. Formation of dew. 



40 


HEAT. 


becomes cool, viz., 1st, by radiation, 2nd, by the contact of air 
which, becoming lighter by absorbing caloric, ascends, and gives 
place to cooler air which in its turn absorbs caloric and rises. 
It is by contact with the earth only, that the atmosphere becomes 
hot; for radiant caloric , either from the sun, or other sources, 
passes through aeriform bodies, without heating them. We, 
therefore, find the upper regions of the air, though nearer the 
source of heat, considerably colder than those next the earth. 

The formation of dew , is connected with this subject. In per¬ 
fectly clear weather, the earth, which is, at all times radiating 
caloric, cools rapidly as soon as the sun sets, for it then radiates 
more than it receives. The atmosphere .contains watery vapour, 
which losing caloric by contiguity to the cool surface of the 
earth, becomes condensed and appears in drops, or minute par¬ 
ticles of moisture, upon the leaves, flowers and grass. 

Latent , Combined , or Insensible Heat. 

83. If equal portions of water, at different temperatures, be 
mixed, the temperature of the mixture will be found an exact 
arithmetical mean between the two original temperatures ; but 
if equal weights of water , and any other liquid be mingled, under 
the same circumstances, the resulting temperature will differ 
from the mean. 

Experiment. Mix a pound of water at 40°, with a pound of 
mercury at 185°, the thermometer will stand at only 45° in the 
mixture ; or if the water be at 185°, and the mercury at 40° the 
mixture will raise the thermometer to 180°. Here, in the first 
case, the 140° of caloric lost by the mercury, only increased the 
temperature of the water by 5°, and in the second case the wa¬ 
ter by losing 5° of heat, raised the mercury by 140°. 

84. Again, if we immerse thermometers in two portions of 
water just taken from the same reservoir, the temperature of each 
will be the same, however unequal their quantities ; yet it is ev¬ 
ident that a quart of water must contain twice as much caloric 
as a pint of the same temperature. It is clear then, that the 
thermometer cannot indicate the absolute quantities of caloric 
contained in bodies ; and that every substance contains some 
heat, (the quantity being peculiar to itself,) which is not percep- 

83. Effect of mixing water of different temperatures, or of mixing 
water and any other liquid. Experiment of mixing water and mercury. 

84. The thermometer does not indicate the absolute quantity of calor¬ 
ic in bodies. Name given to the portion of caloric that does not affect 
the thermometer. Meaning of the terms “ capacity for caloric ajid 
“ specific heat." Opinion of Dr. Black. 



IMPONDERABLES. 


41 


tible by the senses, and does not affect the thermometer. This 
is called by the name of combined , insensible , or latent caloric. 
The power, that a body has of retaining more or less caloric in 
this state, in relation to another body, is called its relative capac¬ 
ity for caloric ; and the relative quantity of heat so retained, is 
called its specific caloric or heat. 

Dr. Black, to whom the discovery of this difference of bodies 
in their relations to heat is due, supposes that the insensible ca¬ 
loric is in a state of chemical combination, by which its proper¬ 
ties are neutralized. 

85. The specific heat of bodies is estimated by comparing 
them with some particular body, of which, the specific heat has 
been taken as unity; that of water is the standard which has 
been generally chosen. The experiment may be made by mix¬ 
ing them separately with equal weights of water of a different 
temperature, and ascertaining the resulting temperature ; or by 
observing the time necessary to bring each to a given tempera¬ 
ture by the same source of heat; for those having the greatest 
specific heat, (or capacity for caloric,) will require the longest 
time ; or, by observing their relative times of cooling under the 
same circumstances ; for those which are longest in heating, are 
also longest in cooling ; or by observing the quantity of ice 
which will be melted by each after having been heated to a given 
temperature ; for those having the greatest specific caloric, will 
melt the most ice. The last method is the foundation of La¬ 
voisier’s Calorimeter.* 

86. In speaking of the specific heat of a particular body, we 
refer to that body in one state only ; for in passing from one state 
to another, it acquires a new specific caloric ; thus, ice has a cer¬ 
tain specific heat, water another, and steam another. Liquids 
have more specific heat than solids, and gases more than liquids ; 
the individuals of each class differing also among themselves. It 
is by absorbing and rendering latent a quantity of caloric, that 
bodies pass from the solid to the liquid, and from the liquid to 
the gaseous state ; and when vapors are reconverted to liquids, 
and liquids to solids, the latent caloric becomes sensible. 

87. From experiments on latent heat, the following conclu¬ 
sions are drawn: 

1st. Every substance has its particular specific caloric, which 
changes when the body changes its form or its composition. 

* Calorimeter is from calor, heat, and metron, measure, a measurer of 
heat. 

85. Mode of estimating the specific heat of bodies. 

87. Specific heat varies with change of state. 

87. Conclusions drawn from experiments on latent heat. Cause of 
the coldness of the upper regions of the air. 



42 


HEAT. 


2nd. Gaseous bodies in becoming denser, lose, and in rarefy¬ 
ing, acquire capacity for caloric ; hence, 

3d. A change of density always occasions a change of tem¬ 
perature. 

One of the reasons assigned for the coldness of the upper re¬ 
gions of air, and the consequent presence of snow and ice on 
high mountain tops, is the rarity of the air at that height; by 
means of which it has a great capacity for heat, absorbs and ren¬ 
ders latent the free caioric from surrounding bodies, and thus re¬ 
mains always at a low temperature. 

Liquefaction . 

88. The phenomena of liquefaction are among the effects of 
caloric. 

If ice be moderately exposed to heat, it will gradually liquefy, 
and the temperature will be at 32° Fahrenheit, during the whole 
process of melting ; but after the last portion of ice is dissolved, 
the water will gradually grow warm, till it attains the tempera¬ 
ture of the surrounding atmosphere. Here the ice has been re¬ 
ceiving caloric which has had no effect in raising its tempera¬ 
ture ; this caloric has been occupied in bringing the ice to the 
liquid state ; it is latent in the water, and is called caloric of flu¬ 
idity. The same thing takes place, whenever a solid becomes 
liquid, as in the dissolving of saline bodies, the fusion of the 
metals, &c. In the latter case, the metal is heated to a certain 
degree, called its fusing point, at which a portion of it begins to 
melt; and all the heat received after this, goes to convert more 
of a solid into a liquid, the temperature remaining stationary till 
all the metal is in a state of fusion ; after which, its temperature 
increases, if the heat be continued. 

89. The heat which has been appropriated in these instances, 
is always given out again , when the liquid becomes solid ; for 
example ; if water be kept entirely motionless, it may be cooled 
by artificial means, several degrees below the freezing point, (32S 
Fahrenheit;) but on agitating it, a portion freezes, and in solid- 
ifying, gives out sufficient caloric to raise the whole to 32° Fah¬ 
renheit. Sulphur and phosphorus, after having been fused, 
may sometimes be cooled to common temperatures without re¬ 
suming their solidity ; but if in this state, they are touched with 
a glass rod or other substance, they instantly solidify, giving out 
their calorie of fluidity. 


88. Caloric of fluidity. 

89. What becomes of the caloric of fluidity, when the liquid is recon¬ 
verted to a solid. 



IMPONDERABLES. 


43 


The fact that caloric disappears during the liquefaction of a 
solid, is usefully applied to the obtaining very low temperatures, 
artificially, by means of freezing mixtures. 

90. Frigorific,* or freezing Mixtures, consist, of certain soluble salts, and 
snow, or pounded ice. The effect depends on the tendency of the salt 
to dissolve in water ; this induces the liquefaction of the ice, by which, 
heat is absorbed ; and the salt dissolving in the water thus formed, re¬ 
moves a further portion of heat. It is obvious that the more rapid the 
liquefaction, the more intense the cold produced, and therefore the most 
effective ; the pulverizing of the materials assists the operation, by has¬ 
tening the process of solution. By the use of equal weights of crystal- 
ized muriate of lime and snow, quicksilver has been frozen. 

91. In employing these mixtures, care must be taken that they are 
thoroughly mingled together. The best vessels for using them, are me¬ 
tallic ores of different sizes, having double sides at a distance of half an 
inch from each other. The article to be frozen, is to be put into the 
smaller vessel, which may then be placed in a larger one, and surround¬ 
ed with the mixture. A double cover is now to be put on, to prevent 
the caloric of the atmosphere from defeating the experiment; and then 
the whole may be left to rest for a time. 

In making the ice cream, the vessel used for containing 
the mixture to be frozen, is usually of tin, and of the form 
represented in the figure ; a is the body jof the vessel, and 
b the handle affixed to the cover, which is made to fit very 
close to exclude the caloric of the atmosphere. The cream, 
now being prepared with sugar, &c., is put into the tin ves¬ 
sel, which is then immersed in pounded ice and salt, or oth¬ 
er freezing mixture, contained in a larger vessel. To fa¬ 
cilitate the freezing process, the vessel containing the cream 
must be occasionally shaken by the handle. When the 
cream is found to be frozen around the sides of the vessel, 
a knife or spoon should be introduced to remove the frozen 
part, so that other portions may take its place. 


Fig. 19. 



LECTURE IV. 

VAPORIZATION.-EBULLITION.-STEAM DISTILLATION.-GASES 

AND VAPORS. 

Vaporization. 

92. Caloric is the cause of vaporization. The conversion of 

* From frigus cold, and facio to make. 

DO. Of what frigorific mixtures consist, and how prepared. 

91. Manner of using these mixtures. Ice cream apparatus. 

92. Evaporation and ebullition. 

















44 


HEAT. 


a liquid into a vapor is termed evaporation when it takes place 
without any visible commotion in the liquid ; and ebullition or 
boiling, when accompanied with such external signs. 

93. Many of the substances with which we are acquainted 
have been brought into the gaseous form by heat; and it is not 
inconsistent with any established theory to suppose that temper¬ 
ature may be raised sufficiently high to sublimate and render gas¬ 
eous all bodies. Such bodies as have never been converted 
into vapor by heat, are said to be fixed ; the substances known to 
be vaporizable are called volatile. 

Solids usually become liquids before they vaporize ; some, 
however, as arsenic and iodine, pass at once from the solid, to 
the aeriform state. 

94. Evaporation is the slow conversion of a body into vapor. 
It takes place whenever a liquid is exposed freely to air. In a 
very few cases, also, solids disappear, slowly, from the same 
cause. The drying of wet clothes, when hung out in the air is 
an example ; and sometimes the vapor may be seen rising 
and passing off. If such clothes are exposed to a fresh and keen 
wind, with the air some degrees above the freezing point, the 
current of air hastens the process of evaporation, and heat is so 
rapidly carried ofl, as to cause the freezing of the remaining 
water, and the cloth is hard and stiff, until further evaporation 
carries off all the water contained within its pores. 

95. The rapidity of evaporation is influenced by the following 
circumstances. 

1st. By the form of the vessel; the evaporation takes place 
only from the exposed surface. A liquid to be evaporated, 
should, therefore, be put into a shallow, but broad vessel. 

2nd. By the moisture , or dryness of the air. The atmosphere 
is capable of retaining only a certain quantity of vapor ; the dry¬ 
er the air, therefore, the more rapid the evaporation. 

3d. By the motion or stillness of the air. Evaporation takes 
place more rapidly when there are currents, by means of which, 
the saturated air is constantly rembved and replaced by dry por¬ 
tions. 

4th. By pressure on the surface. If any liquid be placed under 
the exhausted receiver of an air pump, the pressure of the at¬ 
mosphere being now removed, the evaporation will take place 
with much greater rapidity. 

But in a short time, the receiver would become filled with an atmos¬ 
phere of vapor, which would exert a pressure as the atmosphere didbe- 


93. Fixed and volatile bodies. 
65. Example of evaporation. 




IMPONDERABLES. 


45 


fore, and retard evaporation. If we place under the receiver some sub¬ 
stance capable of absorbing the vapor as fast as it forms, the vacuum 
will be kept up, and the evaporation will continue as rapid as be¬ 
fore. It is found that sulphuric acid has a powerful attraction for watery 
vapor. Professor Leslie has shown that by placing water in a flat dish 
over this acid, and removing the atmospheric pressure by an air pump, 
the rapid evaporation which takes place, renders latent so much of the 
caloric of the water, that a portion of it will freeze. 

96- Upon the plate of an air pump, place a flat, shallow, glass dish, A, 
about half filled with sulphuric acid, and a little above it, a tin or copper 
basin B, three parts filled with water, and a small thermometer C, im¬ 
mersed in the liquid. 


Fig. 20. 



This basin, is supported upon three glass legs D, standing in the acid 
and an air-pump receiver is placed over it. On proceeding to exhaust 
the air, the thermometer gradually sinks; the wafer in consequence of 
the rapidity of its evaporation, appears to boil, and if the apparatus is 
in good order, it freezes in the course of five or ten minutes. The use 
of the surface of sulphuric acid here, is to absorb the aqueous vapor, 
which it does very energetically, and consequently occasions a constant 
call upon the water for its formation. Now, vapor cannot be produced 
without the absorption of heat; and in the case before us, the heat requi¬ 
site to convert one part of the water into vapor , is taken from the other 
fluid portion , which, thus losing the heat that constituted its fluidity, 
becomes solid, or freezes. There is another phenomenon often observa¬ 
ble in this experiment, which is, that the temperature of the water falls 
several degrees below the freezing point, before congelation takes place ; 
but the moment that the water freezes, it rises to 32°, in consequence of 
the escape of the residuary latent heat.” 


96. Professor Leslie’s experiment to show the rapid evapotation of wa¬ 
ter, when the pressure of the atmosphere is removed. 

5 

























46 


HEAT. 


97. By the evaporation of ether under an exhausted receiver, 
water may also be frozen. 

Suppose a thin glass flask, contain¬ 
ing a portion of ether, is placed in a 
wine glaps containing cold water to the 
level at a, and then covered with the 
receiver of an air-pump. On exhaust¬ 
ing the air, the ether will pass into a 
state of vapor. In evaporating, the 
ether takes from the surrounding bod¬ 
ies ; the water in contact with it loses 
its caloric of fluidity , and becomes solicL 
A small animal if exposed to a current 
p of air, while wet with ether, would 
soon die, from privation of vital heat. 
98. Dr. Wollaston’s Cryophorus, or 



Frost-bearer consists of a tube with a bulb, a, and b , at each end. 
One of the bulbs, b y is partly filled with water, and the remaining 

Fig. 22. 




space contains watery vapor ; the atmospheric air having been 
expelled by boiling the liquid, as in making a thermometer. If 
now the empty bulb, a, is immersed in a freezing mixture, the 
watery vapor will be condensed by cold ; a vacuum being form¬ 
ed a new portion of vapor will rise from the water in the other 
bulb, and, in its turn, be condensed ; in a few minutes, the waiter 
in the bulb at b y will be frozen quite solid. 

The bulb may be secured against the admission of caloric, by 
a covered glass, as in the figure at b. 


97. Water frozen by the evaporation of ether. 

98. Cryophorus. 


























IMPONDERABLES. 


47 



99. The pulse glass is 
a small instrument resem¬ 
bling the cryophorus in its 
form. It contains a small 
portion of alcohol, with high¬ 


ly rarefied air. On grasping, with the warm hand, the bulb 
which contains the liquid, a bubbling, resembling boiling, takes 
place ; the alcohol is converted into vapor, and passes over into 
the other bulb. The hand experiences a sensation of intense 
cold, on account of the heat which passes from it into the alco¬ 
hol. The sensible heat of the hand has become latent heat in 
the newly formed vapor* which, if tested by the thermometer, 
would exhibit no increase of temperature ftbove that of the liquid 
from which it had been formed. 

100. 5th. Evaporation is greatly influenced by temperature. Mr. 

Dalton has shown that the quantity of vapor capable of existing 
in a given space depends only on temperature. If a little water 
be put into a dry flask, it will soon yield a quantity of vapor 
which will fill the vessel; and the presence of air in the flask 
will influence only the rapidity with which the vapor will rise, 
by mechanically obstructing its diffusion through the space. 
According to the same philosopher, the air, and other gases, are 
capable of containing a quantity of vapor, up to a certain limit, at 
which they become saturated, and can contain no more ; and the 
quantity they contain at any time depends on their temperature 
and may be accurately estimated. According to him, also, gases 
do not chemically combine with the vapor they may hold ; but 
the two are merely mixed , the particles of one occupying the 
interstices between the particles of the other, without exercising 
either a repulsive, or attractive influence on them. And the 
elastic force, or the pressure exerted by any mixture of gasses 
and vapors is the sum of the pressures of the individual gases and 
vapors. ' • r 

101. The effect of heat in promoting evaporation, is extensively 
useful in chemical operations ; for it is often necessary to re¬ 
move a portion, or the whole of a liquid, when it can be done in 
no other way than by evaporation ; and this is usually effected 
by placing the liquid, contained in a flat dish, on a bed of sand, 
heated by a furnace below. This is called a sand-bath , and facili¬ 
tates the regulation and equal distribution of heat. When evapo- 

^ 99. Pulse glass. 

100. Fifth important circumstance which influences evaporation . Mr. 
Dalton’s discoveries of the effect of temperature on evaporation. 

101. Utility of evaporation in chemical operations. Sand-bath. Effect 
of hastening evaporation by heat. 




HEAT. 


48 


ration is thus accelerated by heat, the vapor forms more or less 
rapidly, till the temperature is raised to a certain point, when 
the portions of the liquid in contact w ith the' heated vessel, are 
converted into vapor, which forcing its way through the liquid, 
rises, in bubbles, to the surface ? and escapes. The agitation of 
the liquid occasioned by this rapid , escape of vapor is . called 
ebullition , or boiling . 

^BUJuLITION. 

102. By the application of heat to a liquid, it is made to boil ; 
that is, it passes into vapor, and usually with some degree of 
sound and agitajion. If a portion of water be placed in a glass 
flask, closely corked and subjected to the heat of a lamp, the 
water will soon begin to boil, its quantity will gradually diminish, 
until the vessel will seem to be empty. But it will be found to 
have the same weight as before the water boiled, therefore it can 
have lost nothing which it contained. Expose this vessel to the 
cold air ; dew will begin to collect upon the inner side of the 
glass, and at length, the same quantity of water as the vessel at 
first contained, will appear at the' bottom, and this water will 
exhibit the same properties, as before evaporation. 

103. Dr. Black instituted some ingenious experiments, to de¬ 
termine the actual loss of heat during the conversion of water 
into steam. He heated water in a tin vessel up to the boiling 
point, and noted the time required for the purpose. The same 
heat was then continued, till the whole of the water was evapo¬ 
rated ; and the time taken up by that process was also noted. 
Now since, on the one hand the accession of heat was constant, 
it was easily computed how high the temperature could have 
been, supposing the rise to have gone on above 212°, in the 
same ratio, as below it; and, on the other, as the temperature of 
the steam was not raised, it was inferred that all the accession of 
heat from 212 c> , was essential to the very state and constitution 
of steam at that temperature ; this quantity was estimated at 
about 810° ; that is to say, that the same quantity of heat which 
is required totally to evaporate boiling water at 212°, would be 
sufficient to raise the water 810°, above the boiling point, or to 
1022 Q , if it had remained in the liquid state. 

102. Cause of ebullition. Change which water undergoes in boiling. 
How is it proved that water loses nothing, and suffers no change in its 
constitution by boiling ? 

103. Inferences drawn from Dr. Black’s experiments upon the heat 
required for converting water into steam. 



IMPONDERABLES. 


49 


104. On the other hand, when steam is again condensed into 
water, it necessarily gives out the latent heat which was essen¬ 
tial to its state of vapor, and which, being then set free, will 
raise the temperature of adjacent bodies, as much more than an 
equal weight of boiling water would do, as the latent heat of 
steam exceeds that of boiling water. 

105. A small steam-boiler a has been contrived for experiments on la¬ 
tent heat. The boiler is furnished with two stop cocks, b and <Z, to the 
latter of which is screwed the pipe e : when the latent heat of vapor is to 
be determined, water is put into the boiler, and made to boil by the ap¬ 
plication of an Argand lamp /: the end of the pipe c, being immersed in 


Fig. 24. 



a given quantity of water in a vessel g, furnished with a thermometer h. 
After the water has boiled for some time, the increase of weight of the 
water in the vessel g may be ascertained, and then the indication of the 
thermometer will, show how much heat has been imparted to the water 
by the condensation of a quantity of steam'equal to the increase of weight. 
The effect thus produced may be compared with that which would re¬ 
sult from the addition of an equal, weight of boiling water; and it will be 
found that a given weight of steam at 212°, has the power of heat¬ 
ing water many times more than an equal weight of water at the same 
temperature. The thermometer c passes through a collar into the boiler a 
for the purpose of ascertaining the heat of its contents. 


104. Heat given out when steam is condensed into water. 

105. Apparatus for experiments on latent heat, mode of using it, with 
Inferences from the changes which are observed. 

5 * 






















































50 


HEAT. 


106. It is probably, the greater affinity of beat for steam, more 
than for water, that makes the boiling point of water so perfectly 
stationary in open vessels over the strongest fires.* 

Every kind of liquid has its own particular temperature at 
which it boils ; and this temperature is called the boiling point 
of that liquid. Beyond this point no liquid can be heated in 
the open air ; all the heat afterwards acquired, being consumed 
in converting the liquid into vapor ; and every vapor, at the 
time of its being evolved, has the same temperature with the 
liquid which yielded it. Thus water, as we have seen, cannot be 
heated under ordinary circumstances, and in open vessels, to a 
higher temperature than 212°, and the steam which rises is also 
at 212° Alcohol boils at 173°, and ether at 96°, yielding vapors 
of those temperatures respectively. 

107. The boiling point of water, may be made to vary with 
circumstances. 1st. The nature of the vessel used has some 
influence ' r Gay Lussac found that the boiling point of water 
rises to 214 Q in a glass vessel, while it would boil af 212° in one of 
iron ; and 2nd., that the introduction of iron filings caused water, 
boiling at 214® in a glass vessel, to yield steam at 212 Q . This 
expedient is often used to facilitate the ebullition of liquids, which 
have a high boiling point: thus, sulphuric acid, which boils with 
violent jerks at 620°, is made to yield its vapor steadily, and 
quietly, by introducing a crumpled piece of platinum-foil. The 
substance added, however, must be such as has no chemical 
action on the liquids. 

But the circumstance which has the greatest influence on the 
boiling point of liquids is 3d pressure. The weight of the 
atmosphere is the only obstacle which prevents many liquids 
from existing as vapors, at ordinary temperatures. Thus, ether 
and alcohol boil under the exhausted receiver of the air pump, 
and water will boil, in a vacuum, at a temperature of 72°. 

108. If water, heated to the boiling point, be withdrawn from 
the fire, the boiling will cease ; let the vessel containing the 
water be placed under the receiver of an air pump, the air being 
exhausted, ebullition will again take place, and will continue, till 
the temperature of the water has fallen below 72°. 

# Lib. of useful Knowledge, art. Chem. page 49. 

106. Why the boiling point of water is stationary in open vessels, with 
different degrees of heat. Meaning of the expression, “ boiling point.” 
Boiling point of water, alcohol, and ether. 

107. Circumstances which cause the boiling point of liquids to vary. 

108. Experiment to show that water boils with less heat when the 
pressure of the atmosphere is removed. 



IMPONDERABLES. 


51 


109. It has been shown that atmospheric pressure raises the boiling 
points of all liquids 140“ Fahrenheit, higher than the temperature at 
which they boil in a vacuum. When the boiling point of a liquid is stat¬ 
ed, it is to be understood that the barometer stood during the experiment, 
at the medium height, or 30 inches. If the mercurial column be higher 
than that, the boiling point will rise, if lower it will fall. The tempera¬ 
ture at which watery, or other vapor, is able to overcome the atmospheric 
pressure and escape, may be used, instead of the height of the mercurial 
column, to ascertain the amount of that pressure; and since the weight 
of the air decreases in a constant ratio as we ascend, water will boil, 
more readily, on the top of a mountain, than on the plain below; so that 
we may ascertain the height of the mountain, by observing the tempera¬ 
ture at which water boils on its summit, allowing 530 feet for each degree 
of Fahrenheit’s thermometer 

110. The effect of diminished pressure may be satisfactorily shown by 
the following. 

Experiment. Fit a stop-cock to the neck of a glass flask ; half fill the 
flask with water, and place it over the flames of a lamp, let it boil a few 
minutes, till the air is all expelled, and the steam escapes freely through 
the open stop-cock. Then remove the lamp, and close the stop-cock; 
the ebullition will instantly cease. But if the flask be suddenly plunged 
into a vessel of cold water, the steam within the flask, which by pressing 
on the liquid prevented the formation of vapor, will be partially condens¬ 
ed, and the boiling will re-commence, and continue till a new atmosphere 
of steam is formed. This may be condensed by a second immersion in 
cold water, and so on, till the temperature of the water within the flask, 
is reduced below the boiling point. 

* l / / ^ 

Steam. 

111. As the boiling point of liquids may be depressed by dimi¬ 
nution of pressure , so the contrary effect may be produced by an 
increase of it. If water be heated in a strong vessel, closed so 
that steam cannot make its escape, its temperature may be raised 
even to a red heat, without ebullition ; the only limit being the 
strength of the vessel to resist the immense expansive force of 
the liquid. If an aperture were suddenly made in the vessel, a 
large quantity of the water would flash at once into steam, with 
explosive violence. When water is heated in a common tea¬ 
kettle, if the lid fits closely, so that the steam when formed can¬ 
not escape, the accumulation of vapor in the upper part of the 
kettle, will soon cause an increased pressure on the surface of the 

109. What is the effect with respect to the boiling point of a liquid 
when the barometer is higher or lower than the medium height ? Why 
does water boil with less heat upon high mountains than at their base ? 

110. Why does a flask of water stop boiling when exposed to a cer¬ 
tain degree of heat, and re-commence boiling on being plunged into cold 
water. 

111. Effect of increased pressure upon the boiling of liquids and con¬ 
sequently, in retarding the formation of steam. 




52 


HEAT. 


water below, and some of it will be forced out at the spout; 
when the steam has thus made room for itself, or if the lid be 
removed, the spouting jet will cease. 

112. Steam generated under pressure, at temperatures above 
the ordinary boiling point, is called high pressure steam ; that 
formed in the usual manner under atmospheric pressure only, is 
called low pressure steam. 

113. All vapors can be condensed into liquids, by coming into 
contact with a cold surface, whereby a part of their latent heat is 
taken away ; or by subjecting them to pressure, in which case, 
also, they yield their caloric of expansion, and the vessels in 
which they are condensed become heated. 

114. Steam, as it issues from an escape pipe, is transparent, 
and nearly invisible ; but a very short distance from ihe mouth 
of the pipe it becomes opake. This is caused by its being con¬ 
densed by the cold air. 

115. Instruments invented to prevent the loss of heat by evaporation 
are called digesters. Papin's digester , is a cylindrical copper vessel, hav¬ 
ing a lid nicely fitted to it, and secured by screws. “ If such a vessel be 
about half filled with water, with the lid closely secured, and then put 
upon the fire, steaih is soon formed ; but having no escape, it presses 
upon the water, and prevents the further formation of steam, till the tem¬ 
perature of the water rises above the boiling point. This heat being con¬ 
veyed to the steam, it now receives another portion of vapor without 
being condensed, and thus the quantity and the elasticity of the steam,are 
continually increasing with the temperature. Water has in this way been 
raised to the temperature of 419°, Fahrenheit. 

116. At the temperature, of 419°, the elasticity of steam is 
1050 times greater than that of atmospheric air ; so that it ex¬ 
erts, upon the inside of the vessel in which it is pent up, a force 
of at least 14700 pounds pressure on each square inch ; a pres¬ 
sure so enormous that few vessels can resist it, and hence have 
occurred many serious accidents, which, in the applications of 
high pressure steam, are now guarded against, by safety valves 
and other similar contrivances. 


112. High and low pressure steam. 

113. How may all be condensed into liquids ? 

114. Transparency of pure steam. 

115. Digesters. Papin’s digester. 

116. Elastic force of steam. 



IMPONDERABLES. 


53 


Fi«\ 25. 


a. 


117. For experiments of this kind upon a 
small and safe Scale, the following is a good 
form of apparatus; — a is a strong glass globe, 
composed of two hemispheres screwed togeth¬ 
er ; a portion of quicksilver is introduced into 
it, and it is then about half filled with water; 
b is a barometer tube passing through a steam- 
tight collar, and dipping into the quicksilver 
at the bottom of the globe : c is a thermometer 
graduated to about 400°, and also passing 
through an air-tight collar : d is a stop-cock, 
and e a large spirit-lamp. - The whole is sup¬ 
ported upon the brass frame, and stand/. 
Upon applying, heat to this vessel, the stop¬ 
cock being closed as soon as the Water boils, it 
will be found that the temperature both of the 
water and of its vapor, increases with the 
pressure, the extent of which, is measured by 
the ascent of the mercury in the barometer 
tube. The thermometer, under an atmospheric 
pressure of thirty inches, being ut 212°, will 
be elevated to 221°, under an additional 
pressure of 5 inches, of meroury ; and to 
269°, under an additional pressure of 30 
inches, or one additional atmosphere; ‘each 
inch oY mercury, above. 36, producing by 
its pressure, a rise of about 192 Q , in the ther¬ 
mometer. The barometer tube also serves the 
purpose of a safety valve, the strength of the 
brass globe being such as to resist a greater 
pressure than that of our atmosphere.* 

118. The latent Caloric of steam may 
be economically employed in heating 
large rooms, by conveying it in pipes; 
and this expedient is sometimes used in 
manufactories of ether and other inflam¬ 
mable articles, where fire would be un¬ 
safe. Water may be soon heated by a 

current of steam passing through, and becoming condensed in it. 

Distillation . 



119. The process of distillation consists in converting substan¬ 
ces into vapor, and condensing this by cooling. The distilling 
apparatus consists of retorts, receivers, alembics and the still and 
worm. In using them, the receiver, or the head of the alembic, 

* Elements of Chemistry, London Ed. 1831. 


117. Apparatus for exhibiting the elastic force of steam. 

118. Economical applications of the latent heat of steam. 

119. What is distillation, and how conducted ? 










54 


HEAT. 


must be kept cool by ice, moistened cloths, or otherwise. On 
a large scale, as in distillation of ardent spirits, the still and worm 
are used, the latter consists of a long, spiral, metallic tube, set in 
a vessel of cold water $ the vapor being conveyed into this, con¬ 
densed by passing over a great extent of cold surface. 

120. The figure explains the simple process of the distillation of 

alcohol. Fig. 26. 

Experiment. “ Into a glass 
alembic a put one part of 
spirit of wine, and seven 
or eight parts of colored water. 
Before putting the mixture 
into the alembic, plunge into 
it a burning paper, and the 
flame will be extinguished. 
This will prove that the mix¬ 
ture is not inflammable. Ap¬ 
ply the heat of a spirit lamp 
i, and the lower part of the 
apparatus will soon become 
dim with moisture f a portion 
of the alcohol will be raised in 
vapor and coming Into contact 
with the sides of the vessel, 
will at first be condensed ; but 
this vessel will very speedily 
become too hot to condense the vapor; it will then ascend into the head 
of the alembic c, and being there condensed, will run down into the re¬ 
ceiver d, where, in a short time will appear a small quantity of pure, color¬ 
less liquid. If this bepoured into an open.vesseljand a piece of burning paper 
applied, it will take fire and burn to dryness. Thus, it will be proved, 
that from a colored, uninflammable mixture, a pure, colorless, inflamma¬ 
ble spirit may be obtained by the process of distillation. 

121. The form of Still most commonly used, is represented in fig. 27: 
a, is the furnace ; b, the capital, or head of the copper still; c, a part of 
the chimney; d, the worm tub, containing cold water for condensing 
the vapor that enters the worm. The vapor, in passing through this 
cold, spiral, metallic tube, becomes condensed apd liquefied, and passes 
from it, in its distilled form, into the vessel beneath.* 



Lib. U. Knowledge, p. 57. 


120, Experiment tp explain the changes in distillation. 

121. Still and worm. 

















IMPONDERABLES. 


55 


Fig. 27. 



122. By the process of distillation, volatile bodies are sepa¬ 
rated from those that are more gross ; for example, by distilling 
salt water, we may obtain fresh water ; the saline matter, remain¬ 
ing in the retort. 

Sometimes, it is necessary to distil substances that would be decom¬ 
posed by too high a heat. For this purpose, the different boiling points of 
liquids afford us the means of regulating the temperature. If, for exam¬ 
ple, we wish to^distil a substance, keeping the heat always at 212°, the 
retort may be set in a basin of water, and fhe heat applied to the latter ; 
if the substance to be distilled requires a little higher temperature, some 
soluble body may be dissolved in the water, which by' its affinity for the 
latter will prevent it from vaporizing at as low a temperature as usual. 
The stronger the solution, the higher the boiling point. We can also 
graduate the heat below the boiling point of water, by using different 
mixtures of alcohol and water, or pure alcohol. 

Gasses and Vapors . 

123. Until recently, aeriform bodies were divided into two 
classes, gases , or permanently elastic fluids and vapors , which are 
easily condensible into liquids. But Mr. Faraday has succeeded, 
by means of intense artificial cold, and very great pressure united, 

122. Distillation of salt water. Means of regulating the temperature 
in distilling. 

123. Distinction between gases and vapors. Mr. Faraday’s experi¬ 
ments. 














56 


HEAT. 


in liquefying many of the gases ; and it is now thought probable, 
that all of them are the vapors of liquids having boiling points 
very far below any natural temperature. The term pas, however, 
is still applied to those bodies which retain the aeriform state 
under ordinary pressures and temperatures. 

The different gases require very different degrees of pressure and re¬ 
duction of temperature for their liquefaction; all of the liquids thus ob¬ 
tained, have so strong a tendency to resume their elastic state, that, on 
breaking the tube in which they are confine^, they expand with great 
force, producing of course, intense cold, and frequently exploding, so as 
to endanger the operator. 

124. Vapors, so long as they remain uncondensed, have all 
the physical properties of gases ; and their elasticity and con¬ 
densibility render them useful as a moving power. 

The actiop of the steam engine depends chiefly upon two prop¬ 
erties of steam ; viz. expansive force, and easy condensation. 

The figure will shew how steam acts as a 
moving or propelling power. Let a repre¬ 
sent a glass tube with a bulb at its lower end. 
It is held in a brass ring to which a wooden 
handle, b is attached, and contains a piston, 
c, which, as well as its rod is perforated, and 
may be opened or closed by the screw at top, 
d ; it is kept central by passing through a 
slice of cork at e. A little water being pour¬ 
ed into the bulb, and carefully heated over a 
spirit lamp, and the aperture in the piston 
being open, the air is expelled, and when 
steam freely follows it, the screw may be 
closed- On applying cold to the bulb, the in¬ 
cluded steam is condensed, and a vacuum 
formed, which causes the descent of the pis¬ 
ton, in consequence of the air pressing on it 
from above. On again holding the bulb 
over the lamp, steam is re-produced, and the 
piston again forced up, and these alternate 
motions may be repeatedly performed by the 
alternate applications of heat and cold. 
Therefore the ascent of the piston of a steam 
engine, we perceive, is caused by the expans - 
ive force or elasticity of steam forcing the pis¬ 
ton upward. 

125. In the old steam engines, the descend¬ 
ing stroke is produced by injecting cold 
water, which condenses the steam, and pro¬ 
duces a partial vacuum ; the atmospheric pressure then counterbalances 
the force beneath the piston, and impels it downward. Watt’s great 


124. Properties of vapors which render them useful as a power. Ex¬ 
planation of the action of the steam engine. 

125. Manner in which the descending stroke of the steam piston was 
formerly produced. Watt’s improvement. 
















IMPONDERABLES. 


57 


improvement in the steam engine consists in conveying off the steam 
after it has performed the office of raising the piston, and condensing it 
in a separate vessel; thus avoiding the great loss of heat formerly incur¬ 
red by cooling the cylinder at each stroke of the piston. 

12b'. Mr Dalton has deduced from experiments, the interesting law, 
that the vapors of all liquids have the same elasticity at the 
same distance above, or below their respective boiling points; 
thus the vapor of ether at 87°, has the same tension or elastic force as 
that of water at 202 a , or that of alcohol at 163°, those temperatures 
being respectively ten degrees below the boiling points of the different 
liquids. From this, also, it results that the vapor of mercury at 60°, (the 
boiling point being 680“,*) has a tension equal to that of water 620°below 
its boiling point; that is, to that of water at 408° below zero; which is 
so small that it could not overcome the pressure of atmosphere. It is, 
therefore, concluded that mercury and other liquids having very high 
points of ebullition do not evaporate at common temperatures. 


LECTURE V. 

( ^ * . }* '.., ft 

LIGHT.-DECOMPOSITION OF LIGHT.—ILLUMINATING, HEATING, 

COLORING AND MAGNETIC RAYS.—FLAME.—PHOSPHORESCENCE. 

127. We shall consider light like caloric, as matter, under a 
particular form. It is supposed to be a subtle fluid, imponderable, 
incapable of being confined, universally diffused, and moving 
with immense velocity. The velocity of light is estimated at 
200.000 miles in a second. Light is subject to radiation and re¬ 
flection in the same manner and according to the same laws as 
caloric ; the bodies which reflect the one, being also reflectors of 
the other ; the metals when polished, are, therefore, the best 
reflectors of light. 

128. Light is the agent of vision or of seeing. Rays of light 
thrown out from all the points of a luminous body, are collected 
by the tens of the eye, and thrown upon the retina , producing 
there the image of the radiating body. Objects, not of themselves 
luminous, are seen by means of light thrown upon them from 
the sun or other sources, and reflected to the eye of the observer- 

* According to Dulong. 

126. Mr. Dalton’s discovery of the law which governs the elasticity of 
vapors. Elastic force of the vapor of mercury at 60°. 

127. Definition of light. Velocity. Radiation and reflection. 

128. Light the cause of vision. 

6 




58 


LIGHT. 


129. Besides the properties of radiation and reflection, light 
has still another quality in common with caloric : viz., that of 
being refracted , or bent out of its course into a new direction. 
If light passes into a medium more dense than that in which it 
has been moving, it is refracted toward a perpendicular to the 
surface of the new medium, erected at the point of incidence ; 
if it passes from a denser to a rarer medium, the deflection is in 
a contrary sense, or from the perpendicular. It is the refraction 
of light, that causes a stick partly immersed in water to appear 
bent ; and the different densities of the warm air over a stove, 
and the colder air on each side of it, cause objects seen through 
both to appear distorted. 

130. Bodies which permit light to pass freely through them, 
are called transparent; those which do not, opake. A perfectly 
transparent body cannot reflect light, and therefore cannot be vis¬ 
ible. Although the solar rays possess heating power, transpa¬ 
rent bodies are not heated when light passes through them; 
neither do reflectors of light absorb any of the caloric of the 
rays. For this reason, concave mirrors and burning glasses re¬ 
main cool themselves, though they concentrate and transmit light 
and heat to an intense degree, upon bodies in their foci . 

131. It is remarkable that a close~relation seems to exist be¬ 
tween the combustible and refracting powers of substances ; the 
most combustible, being also the most refractive, provided they 
be at the same time transparent. Hydrogen, the most powerful¬ 
ly combustible of the gases, has the highest refracting power ; 
oxygen, the most eminent supporter of combustion, is the most 
feeble refractor of light. The diamond, and water were pro¬ 
nounced by Newton to contain combustibles, long before their 
chemical nature was known. 

Decomposition of Light. 

132. By means of its property of refraction, Newton was en¬ 
abled to prove that light is a compound body. 

A ray of solar light received on a transparent, triangular prism 
either of glass or other transparent substance, is found after its 
passage, to be resolved into seven rays or colors ; their separa¬ 
tion being caused by the different refrangibility of the rays. The 


129. Refraction. 

130. Transparent and opake bodies. Why reflectors and lenses are 
not heated by the calorific rays which they reflect or transmit. 

131. Connection between the combustible and refracting powers of 
substances. 

132. Compound nature of light. Solar spectrum. Rainbow. New¬ 
ton’s experiment. 



IMPONDERABLES. 


59 


colored image is called the solar spectrum , and is composed as 
follows : (beginning with the most refrangible ray, and proceed¬ 
ing in order) violet , indigo , blue, green , yellow , orange , and red 
The phenomenon of the rainbow is produced by the decomposi¬ 
tion of light in passing through drops of rain. Newton was led 
to discover this, by observing that drops of rain exhibited a va¬ 
riety of colors when the sun shone upon them, and also that 
the arrangement of the colors of the rainbow was always the 
same. He believed these colors thus produced, to be the result 
of the decomposition of light. To prove this, he made use of 
the following experiment .—He caused a window shutter to be 
closed, and placing a prism before a hole in the shutter, the light 
which issued through the aperture was refracted , or bent out of 
its course towards the ground, and thrown upwards upon the op¬ 
posite wall. Here the circular beam of light was separated into 
seven colors ; the upper or most refracted ray was the violet, 
then indigo, blue, green, yellow, orange, and lastly red, which 
was the least refracted. 

133. Certain bodies have the property of decomposing the light 
given out by substances burning in contact with them, and of 
yielding only one ray. 

Experiment. Moisten some table salt with alcohol, and set 
the latter on fire in a dark room ; the flame contains only the 
yellow ray, and the human face seen by its light, has a ghastly 
and corpse-like hue ; a red handkerchief, or anything not capa¬ 
ble of reflecting the yellow ray, appears black. Borax gives a 
green, and the salts of strontia a red tinge to the flame of alco¬ 
hol. These effects are attributed to a decomposition of the rays 
of light by the salt, all the primary colors being absorbed, ex¬ 
cept that which is visible in the flame. Such lights are called 
monochromatic*. 

Illuminating , Heating , Coloring and Magnetic Rays. 

134. The illuminating power of the different rays is by no 
means equal, the greatest being in the yellow and green, less iu 
the blue and red, still less in the indigo, and comparatively little 
in the violet. This explains the familiar fact that a room of 
which the walls are yellow or pale green, is much more easily 
lighted, than one painted blue or any other color. 

* From the Greek monos , one, and chroma , color. 


133. Light which exibits but one ray. Experiment with table salt 
and alcohol, borax and strontia. Cause of these effects. 

134. Illuminating power of the different rays. 



60 


LIGHT. 


135. The heating power of the colored rays is greatest in the 
red, and decreases towards the violet; but it is found that there 
are invisible rays , beyond the red,.(and therefore less refrangible,) 
in which is contained the greatest heat of the spectrum. It had 
been supposed by philosophers, that the heating power in the 
spectrum would be proportioned to the quantity of light, and 
therefore the yellow was accounted the warmest of the colored 
rays. But Dr. Herschel, by a series of experiments, proved 
that the heating power gradually increased from the violet ray 
to the red. He ascertained, moreover, that the thermometer 
continued to rise when placed beyond the red extremity of the 
spectrum, where' not a single ray of light was seen. From these 
phenomena, he inferred that there were invisible rays of pure caloric 
in the light of the sun, which were less refrangible than even red 
light. 

The following are the measures of the temperature of the different 
rays. 

CoZor, 

Blue, 

Green, 

Yellow, 

Red, 

Beyond red, 

136. There seem also to exist other rays in the spectrum, out¬ 
side of the violet ; in these rays, resides the power which light 
possesses of producing certain chemical phenomena. 

Experiment. Moisten some white paper with solution of the nitrate of 
silver , (lunar caustic ,) and lay it in the sun, the paper will be blackened ; 
the nitrate being decomposed by the agency of light. The durable ink 
used for marking linen, is made of the same material, and is blackened 
by the same means. . If the moistened paper is exposed to the action of 
the spectrum, the greatest effect will be perceived just out-side of the 
violet ray : and the action decreases, in receding irom that till it becomes 
scarcely perceptible; The chemical agency of light is, therefore, at¬ 
tributed to certain invisible rays, more refrangible than the violet, and 
which are called the chemical or deoxydizing rays; and if any of the 
colored rays seem to possess the same power, in a degree, it is probably 
owing to the imperfect refraction, which does not completely separate 
them. 

137. The most refrangible rays possess also the property of 
rendering steel or iron magnetic. This property is most remarka¬ 
ble in the violet, and decreases to the yellow, where it ceases en¬ 
tirely. 


135. Heating power of the colored rays. Dr. Herschel’s experiments 
Temperature of the different rays. 

136. Chemical or deoxydizing rays. 

137. Magnetic rays. 


Temperature. 
56° Fahrenheit. 
58° “ 

62° “ 

T2° “ 

79? “ 




IMPONDERABLES. 


61 


138. The light of the sun consists, as we find, of three kinds 
of rays ; the colorific or illuminating rays, calorific or heating rays, 
and the chemical or deoxydizing rays. The chemically acting 
rays, are the most refrangible, the colorific, the least so, and the 
calorific possess a mean degree of refrangibility. 

139. The principal sources of light, are three; 1st, the sun ; 
2nd, incandescent or heated bodies; phosphorescent bodies. 

140. Flame. A solid body heated to between 600° and 700°, be¬ 
gins to be luminous in the dark, and glows by day light, at about 
1000°; it is then said to be incandescent. The color of incan¬ 
descent bodies, changes as the heat is raised, passing through 
the shades of cherry red, dull red, bright red, up to a white heat. 
Flames consist of incandescent, gaseous matter, and their tem¬ 
perature is far above the white heat of solids. The luminous 
property of flame is derived from solid matter diffused through it; 
and its illuminating power is not at all in proportion to its heat: 
for the heat of flame is, under certain circumstances, known to 
be very intense when the light which it emits is exceedingly 
feeble. Hydrogen gas is considered the purest form of flame 
which we can exhibit; and yet the light which it emits is so 
faint that, in day-light it can hardly be seen; yet its heat at the 
same time is so intense, that an iron wire held in it, will soon 
be melted or burned. In this process the hydrogen will become 
exceedingly luminous, as the metallic wire ignites. So if we 
scatter fine dust, such as sifted magnesia, or any other solid sub¬ 
stance not of itself inflammable, upon the pale flame of hydro¬ 
gen, the light of it will be greatly increased. 

141. The brilliancy derived from the flame of our common 
candles and lamps, is chiefly owing to the carbon blended with 
the oily substances and burning in the flame. If this substance 
exists in too large a quantity, it will cause the flame to throw off 
a disagreeable smoke, offensive to the smell, and injurious to the 
walls and furniture of a room. 

142. As flame depends upon an intense heat for its existence, 
consequently anything that will reduce its temperature, that is, 
anything that will cool it, will extinguish it. A small flame for 
instance, will be extinguished by bringing a large mass of cold 
iron near it; the metal absorbs the heat. 


138. Refrangibility of the three kinds of rays. 

139 Sources of light. 

140. Incandescent bodies. Flame. Cause of the luminous appear¬ 
ance of flame. Faint light of the flame of hydrogen. 

141. Flame of candles and lamps. 

142. Flame extinguished by withdrawing caloric. 

6* 



62 


LIGHT. 


143. Phosphoresence. Some animal .bodies during life, and 
some animal and vegetable bodies, such as fish and certain kinds 
of wood, in a state of putrefaction give out silvery light, which 
is termed phosphorescent. 

The sea, also when agitated at night, appears phosphorescent. 
Thus the track of a vessel is often marked by a line of soft and 
beautiful light, formerly supposed to be owing to phosphores¬ 
cent matter held in solution. But according to some late observa¬ 
tions, this luminous property of the sea, is owing to collections of 
minute ovae or eggs of animalculae, which float in slimy masses 
over the water. 

A seeond class of phosphorescent bodies give out light only 
when heated, as lard, tallow, &c. which exhibit this property at 
or near the boiling point. 

A third class consists of bodies called solar phosphori ; these, 
after being exposed to the sun’s rays, are luminous in the dark, 
at common temperatures. Some suppose the phosphorescent 
property of these bodies, is owing to their absorbing the sun’s 
light, and giving it off unchanged in the dark, the lighter body 
imparting light to the darker one, as a warmer body imparts ca¬ 
loric to a colder one. But as these substances are prepared with 
sulphur, charcoal and other highly inflammable materials, the 
light which they give off in the dark, may be owing to the slow 
combination of the sulphur, &c. with the oxygen of the air, or 
otherwise by sloiv spontaneous combustion. 

The Bolognian phosphorus is prepared by making into small rolls, 
sulphate of baryta , and heating them in beds of fine charcoal. It is pre¬ 
served in closely stopped bottles; the phosphorescent property, when 
it disappears, is restored by again heating with charcoal. Baldwin's 
phosphorus is nitrate of lime fused at a low heat. Canton's phosphorus 
is made by heating oyster shells to redness, with sulphur. 

Photometers * are instruments for measuring the intensity of light, Les 
lie's photometer consists of a differential thermometer, of which one bulb 
is black, and the whole inclosed within a glass shade. It depends on 
the principle that solar light is always accompanied with the same pro¬ 
portion of heat. If a photometer thus constructed be so placed as to re¬ 
ceive the sun’s rays, the expansion of air in the black bulb, will impel 
the liquid to rise in the white one, 

* From phos, light, and metron to measure. 

143. Phosphorescent light. Phosphorescence of the sea. Second 
class of phosphorescent bodies. Third class, or solar phosphori. Pho¬ 
tometers. 



IMPONDERABLES. 


63 


LECTURE VI. 

GALVANISM. 

(Note. The young Student , or the Beginner will do well to omit thp 
subject of Galvanism, until going over the work for a review.,) 

144. The subject of Electricity is intimately connected both 
with Natural Philosophy and Chemistry. As a chemical agent, 
it is chiefly confined to the department of Galvanism. 

The earliest notice of any fact connected with Galvanism is 
found in a book entitled “ The general theory of Pleasures,” 
published in 1767, by a German metaphysician named Sultzer. 
It is there mentioned that a peculiar taste is excited when two 
slips of different metals, one lying on the tongue, and the other 
under it, are made to touch each other. This writer, however, 
gave no satisfactory explanation of the phenomena; and it at¬ 
tracted little attention till 1790, when it acquired importance from 
the discovery made by Galvani a distinguished professor of Anat¬ 
omy at Bologna; this philosopher had for some time, entertained 
the opinion that electricity was concerned in producing the mus¬ 
cular motions of animals; and his!belief was strengthened, by 
observing, that when the limbs of some recently skinned frogs, 
lying on his table, were accidentally touched with a knife (the 
electric machine being in operation at the same time) convulsive 
motions were produced. In pursuing his researches on the sub¬ 
ject, he found that the same result would be obtained, whenever 
two metals were made to touch each other, while one was in 
contact with the nerves and the other metal in contact with the 
muscles of the frog. 


Fig. 29. 



o 


144. Electricity as a chemical agent. History of Galvanism. Obser¬ 
vations and experiments of Galvani. 






64 


LIGHT. 


The figure represents, at a a, nerves in the leg of a frog, from which 
the skin is removed; at b is a silver wire passed under the nerves. A 
piece of zinc c c, being now brought into contact both with the silver, 
and a muscular or fleshy part of the legs, the Galvanic effects are exhib- 
ted. 

Galvani concluded that the nerves and muscles of living ani¬ 
mals, are charged with electricity developed in the brain ; and 
that, whenever a communication is; made between them by 
means of a conductor, the equilibrium is restored, and motion 
produced. 

145. Among the many who zealously examined and discussed 
these new phenomena, was Volta , a distinguished electrician of 
Pavia. He made numerous experiments on the subject, and ar¬ 
rived at the conclusion, that the motions were, indeed, produced 
by electricity, not generated, however, as Galvani supposed, in 
the animal system, but excited by the contact of the metals them¬ 
selves. But notwithstanding the identity, now well established, 
of common electricity with the Animal electricity of Galvani, 
certain modifications of its character and applications, as well as 
the different modes of producing it, have caused the name Gal¬ 
vanism to be still retained. 

146. Volta constructed the pile which is distinguished by his 
name, and which has greatly contributed to the advancement of 
chemical science, though now superceded by improvements upon 
the original invention. 

Before we describe effects of the Voltaic pile, it is necessary 
to premise the following facts. 

1st. Whenever two plates of different metals are made to touch 
each other by their broad surfaces, electric excitement is pro¬ 
duced. 

2nd. If the plates be separated by means of an insulating han¬ 
dle, one of them will be found positively and the other negatively 
excited. 

3d. The plates being of equal surfaces, the positive excite¬ 
ment of one, will be equal in intensity to the negative excite¬ 
ment of the other. 

4th. Other circumstances being the same, the degree of ex¬ 
citement will be the greater, as the metals differ more in their 
degrees of affinity for oxygen. 

5th. The more oxydable of the two metals will always become 
positively excited, and the other negatively. 


145. Opinions of Volta. 

146. Voltaic pile. Facts connected with the developement of electric¬ 
ity by means of the Voltaic pile, or Galvanism. 



IMPONDERABLES. 


65 


are the metals conmonly used in gal- 

The cut represents a vessel containing 
an acid, much diluted with water, and two 
plates, the one of zink, the other of copper, 
(as shown by the letters Z and C ;) to each 
plate is soldi red a piece of wire, the two 
ends of which meet in the center, opposite 
the place of insertion. This is called a 
simple galvanic circle. It is supposed that 
when in operation, there is, in such a cir¬ 
cle, a continued current of electricity, 
flowing in the direction of the arrows from 
the zink to the fluid, from the fluid to the 
copper, and from the copper <back to the zink. When the wires do not 
communicate, the galvanic circle is saidto.be broken. The wire attach¬ 
ed to the copper plate is negative , that to the zink plate positive. The 
wires are also called poles ; thus we say, the copper is the negative pole , 
and the zink , the positive pole. 

148. The quantity of electricity developed by a single pair of plates 
being very small, Volta endeavored to devise means of increasing it; and 
was finally led to the invention of the Voltaic Pile. This instrument 
consists of pairs of zink and copper plates, one above another. Each pair 
is called a simple element of the pile, the whole consisting of a series of 
simple elements or circles. Between each pair of plates is placed a 
piece of cloth wet with weak acid. 

The figure repesents a Voltaic pile , com¬ 
mencing with zink, Z, and ending with cop¬ 
per C. The wires which meet in the center 
are the two poles. The direction in which 
the arrows point, is that of the electric cur¬ 
rent. In constructing the Voltaic pile, from 
thirty to fifty plates of copper, and as many 
of zink, are generally used; these are placed 
in regular order, each pair of plates being 
separated by a piece of cloth ; thus a regular 
succession of copper, zink and cloth, is kept up through the whole series. 
The pieces of'cloth should be somewhat smaller than the metallic plates, 
and should not be so moist as to yield any of the liquid by the pressure 
of the superincumbent metals. The pile is contained in a frame com¬ 
posed of a base and cap of dry varnished wood, connected by stout rods 
of glass. 

149. The pile is capable of affecting the electrometer, and of producing 
muscular action in a much greater degree than the single pair of plates. 
The zink being positive and copper negative, the electric equilibrium is 
restored on bringing them into communication by means of wires con¬ 
nected with each ; as it is when the coatings of a charged Leyden phial* 

* See Lectures on Natural Philosophy for a description of the Leyden 
phial or jar. 


Fig. 31. 



147. Zinc and copper, 
vanic experiments. 

Fig. 30. 



147. Metals commonly used in galvanic experiments. Galvanic circle. 

Negative and'positive poles. r ' 

148. Construction of the Voltaic pile. Number and arrangement of 
plates. 





















66 


GALVANISM. 


are connected. But the causes of excitement being still in the pile, the 
equilibrium is instantly disturbed again, so that a continuous stream of 
the galvanic fluid is produced : that is one of the most striking differ¬ 
ences between the action of the pile and that of the common electric 
machine. By means of the pile, the Leyden phial may be charged and 
the effects of the latter are precisely the same as when charged in the 
usual manner. If the two extremes of the pile are touched at once by 
tire moistened fingers, a shock is felt differing little in kind from that 
produced by the phial, but much less in degree ; but if, after the first 
effect, the contact be still kept up, a continuous and painful thrilling 
sensation is perceived ; and if the electric current traverses any wound, 
burn, or excoiration, it causes it to spiart severely. Volta remarked that 
the pain was greater on the side toward the negative pole ; a circum¬ 
stance in which Galvanism'resembles common electricity. 

150. Any number of piles may be combined by connecting the ex¬ 
treme copper plate, or negative pole of the first, with the extreme zink 
plate, ox positive pole of the second, and so on ; and all the .effects of the 
pile will be increased according to the number of simple elements , or 
pairs of plates. 

This form of the pile is not now in use, as others more powerful and 
more convenient have been substituted. 

151. One of the first of these was Cruickshank’s trough, commonly 
called the Galvanic battery; it consists of a trough of dry woed, divided 


Fig. 32. 


(\ n 




into cells, by partitions placed at equal distances ; each partition is made 
of a plate of zink, and a plate of copper previously soldered together and 
fitted accurately into a groove cut in the wood; the joints being made 
perfectly tight with cement. The same order of arrangement must be 

149. Action of the Voltaic pile. Differences and resemblances in the 
action of the Voltaic pile and the electrical machine. 

150. Connection of piles. 

151. Galvanic battery. 
























IMPONDERABLES. 


67 


observed as in the pile. This instrument is put into operation by filling 
all the cells about two thirds full of a saline or acid solution. Its effects 
are more powerful than those of the pile, and may be increased by con¬ 
necting several troughs in the manner we have just described, (see § 50.) 

152. The actual contact of the metals, is not necessary, as is seen in 
the construction of Volta’s chain of cups, commonly known as the 

11 Couronne des Tasses 
This arrangement, of which 
the effects are greater than 
those of a pile of equal dimen¬ 
sions, consists of any number 
of pairs of zink and copper 
plates generally about one 
and a half inch square ; the 
zink and copper plate of each 
pair are connected by a wire 
bent in the form of an invert¬ 
ed U : and the different ele¬ 
ments are immersed in cups 
or glasses of acid, or saline 
liquids, in such a manner 
that the zink plate of one 
pair shall be in the same ves¬ 
sel with the copper of the succeeding. Thus the different cups are con¬ 
nected only by the wire which joins the two members of each element: 
and the different elements act on each other only through the medium 
of the intervening liquid. The two extreme plates which are not im¬ 
mersed in the liquid, are not taken into the account, and may be used as 
means of connecting the two poles of the row. 

The electricity is supposed to be excited by the mutual action of the 
surfaces of zink and copper, opposed to each other in the same cup, and 
is conveyed from one cup to another by means of the wire which con¬ 
nects two successive cups. 

153. Many new arrangements and modifications of the battery have 
been proposed ; the most important is that of Dr. Wollaston. Observing 
that in the trough of Cruickshank the effect of one zink, and one copper 
surface in each pair was lost, by soldering them together, he proposed to 
use double copper plates or to bend the copper plate so that it should en¬ 
tirely surround the zink one, but without allowing the two to touch each 
other. In this way each zink surface is opposed to one of copper, and 
the power is increased by one half. Batteries are now generally con¬ 
structed on this principle : and a further improvement is made by con¬ 
necting all the plates to a bar of dry wood, by means of which they can be 
removed at pleasure ; the trough is made of porcelain or some other non¬ 
conductor, and is divided into cells by partitions of the same material. 

* Couronne des Tasses , pronounced hour on da tas , literally a crown 
of cups. 



152. Couronne des Tasses. 

153. Dr. Wollaston’s improved battery. 




68 


GALVANISM. 


Fig. 34. 



Effects of Galvanism . 


154. While the phenemena of galvanism and electricity seem 
to be produced by the same agent , they differ remarkably in the 
following particulars, viz. : 1st, in the greater quantity of the 
electric fluid developed by the galvanic battery, 2nd, in its low 
intensity, and 3d, in the incessant renewal of the excitement as 
often as the equilibrium is restored, so as to produce a continu¬ 
ous current. To the last circumstance, is attributable the 
superiority of galvanism over electricity, in producing chemical 
decomposition. 

155. The igniting effects of the galvanic pile are very re¬ 
markable. 

When the two poles of a battery in action are connected by 
a small wire, the latter becomes intensely heated and gives out 
a light so vivid, that the eye ean scarcely endure it. With a 
powerful battery, substances not fusible by any other means, 
are melted almost instantly. Even platinum is melted by it, as 
readily as wax by the flame of a candle. Of all substances, char¬ 
coal emits the most intensly, brilliant light. To perform this 
experiment, two slender slips of dense charcoal, or of plumbago,* 

* Black lead. 


154. Difference between electricity and galvanism. 

155. Igniting effects of galvanism. 


















IMPONDERABLES. 


69 


should be selected, scraped to a point, and fixed to each of the 
connecting wires. The battery being now put into action, and 
the charcoal points made to touch by means of insulating handles 
attached to the connecting wires, they immediately become 
vividly ignited ; and if very slowly separated, an arc of intense 
light will fill the space between them. With the great battery 
of the Royal Institution at London, consisting of 2000 pairs of 
plates, an arc appeared four inches in length, and the heat exist* 
ing there was so great as to fuse whatever substance was placed 
in it. Wires, even of the least oxidable of the metals, being 
made the medium of connection between the poles, may be burnt 
almost instantly. 

156. Some very brilliant combustions may be exhibited in 
the following manner. Let a quantity of mercury, contained in 
a fiat dish, be connected with the negative pole of a strong bat¬ 
tery ; attach to the positive wire whatever is to be subjected 
to experiment, and make it touch the surface of the mercury. A 
point of fine iron wire burns in this manner with great rapidity, 
giving off vivid sparks in all directions, and producing an ap¬ 
pearance like that of a brilliant star ; the reflection from the 
bright surface of the mercury adding to its beauty. Gold- 
leaf burns with a beautiful green light the instant it touches 
the mercury, and is immediately converted into the purple oxide 
of gold. Silver and copper leaf, and even platinum wire, under¬ 
go vivid combustion. It is necessary to keep the surface of the 
mercury quite clean during these experiments, that its conducting 
power may not be impaired. 

157. If the two connecting wires of a battery are immersed 
in water, so that their points shall be within a short distance of 
each other, an effervescence, arising from the evolution of gas, 
will be immediately observed ; and the experiment may be so 
conducted, that the gas can be collected. When collected, it 
will be found to consist of oxygen and hydrogen, mixed in pre¬ 
cisely the proportion for forming water. The hydrogen is always 
evolved at the negative pole , and the oxygen at the positive ; and by 
a contrivance of Dr. Wollaston, they may be collected and ex¬ 
hibited separately. 


156. Combustion of substances placed on mercury by means of the 
battery. 

157. Decomposition of water by means of the battery. Experiment 
with a bent glass tube. Experiment with two straight tubes. 

7 




70 


GALVANISM. 


Fig. 35. 



Fig. 36. 


This little instrument consists of a 
bent glass tube. At the bend is a 
small hole through the lower side of the 
tube ; each leg of the instrument is 
corked air tight. Through the corks, 
two platinum wires are passed, extend¬ 
ing through the whole lengths of their 
respective portions of the tube, and al¬ 
most meeting each other at the angle. 
If this instrument be immersed in a 
vessel of water, and each of the wires 
connected with one of the poles of a 
galvanic battery, the two portions of 
the tube will shortly be found to con¬ 
tain gas; that in the positive part will 
be oxygen , in the negative hydrogen ; 
and the hydrogen will be in bulk, 
twice that of the oxygen ; such being 
the proportions in which the gases 
unite to form water. But it is not necessary that the water decomposed, 
should be all in the same vessel. The experiment succeeds equally well, 

if two straight tubes, open at their 
lower end, are immersed in separate 
vessels of water, provided the two ves¬ 
sels communicate by means of moisten¬ 
ed fibres of cotton. To effect the de¬ 
composition of water, only a weak 
galvanic battery is required ; the vol¬ 
taic pile, or a trough of 12 pairs of 4 
inch plates being, sufficient. Other 
compounds, of which the constituents 
are united by a stronger force, may be 
resolved into their parts by proportion¬ 
ally increasing the number of plates. 

158.We will now explain some 
of the most important chemical 
properties of acids and alkalies. 
Acids have the property of changing 
to red, the blue color of certain veg¬ 
etable infusions, as that of violets, 
or of purple cabbage. Alkalies , on the contrary, change the 
same blue infusions to green ; and a color which has been chang¬ 
ed by one of these substances, may be restored by the, other. 
Salts are chemical compounds of an acid and an alkali ; and 
when the two are united in proper proportions, their characteris¬ 
tic properties are entirely disguised, and the salt is called 
neutral 

159. If we disolve in water, some Glauber’s salt or sulphate of 
soda, (composed of sulphuric acid and soda,) and add to the solu- 



158. Characteristics of acids, alkalies, salts. 










IMPONDERABLES. 


71 


lion, some blue infusion of cabbage, the color will remain unal¬ 
tered. But if this solution be subjected to the action of a 
galvanic battery of sufficient power, the liquid in the positive 
tube, will very soon become red, proving the presence of an 
acid there, while at the same time, the negative tube will contain 
an alkali, as will be shown by the liquid in it, becoming green. 
Now this acid and alkali could only arise from the decomposition 
of the sulphate of soda ; and we are able, otherwise, to show 
that the contents of the two tubes, being mixed, will reproduce 
this salt. The sulphuric acid, and soda are both compounds, 
each containing oxygen, united to a peculiar combustible body ;* 
and by a galvanic arrangement of high power, we are able to 
resolve the acid and alkali into their elementary parts, that is, to 
their ultimate analysis. 

160. In all cases of proximatef analysis of salts, by the gal¬ 
vanic battery, the acid will be found at the positive pole, and the 
alkali at the negative ; and, whenever by ultimate analysis in 
this way, we resolve a substance into elements, of which one is 
combustible , and the other non-combustible , the latter will be found 
at the positive, and the former at the negative pole. 

Even if different vessels are used, the elements will pass unperceived 
from one to the other, so as to arrange themselves invariably at the pole 
which most strongly attracts them ; and during the action of galvanism, 
their usual chemical affinities are suspended or counteracted ; for they 
may be even made to pass without combination through bodies with which 
they would combine under other circumstances. Sulphuric acid, for 
example, has a stronger tendency to unite with potassa than with soda ; 
but if we take three cups, connecting them by fibres of moist amianthust 
or cotton, fill the two extreme cups with a solution of sulphate of soda, 
and the middle one with a solution of potassa, and then make the ex¬ 
tremes communicate with the poles of the battery, the decomposition will 
take place as before; and no sulphate of potassa will be formed in 
the center cup, though the sulphuric acid which arises from the 
decomposition of the salt in the negative cup, must evidently pass 
through the solution of potassa, on its way to the positive pole. If, 
however, the substance in the intermediate vessel, be one capable of 
forming an insoluble compound with either of the bodies which are thus 
made to traverse it, that compound will be formed; for example, if 

* Sulphuric acid is composed of sluphur and oxygen , soda of a metal 
called sodium united with oxygen. 

t The analysis of sulphate of soda into the acid and the alkali is the 
proximate analysis ; the farther analysis of sulphuric acid and soda into 
three simple elements is the ultimate or last analysis. 

X Flexible asbestos. 


159. Decomposition of a salt by the galvanic battery. What would be 
the ultimate analysis of Glauber’s salt P 

160. What takes place in all cases of proximate and ultimate analysis 
of salts by the galvanic battery ? Decomposition of insoluble salts. 



72 


GALVANISM. 


solution of baryta be used instead of potassa in the last experiment, the 
sulphate of baryta will be formed and will fall to the bottom as an inso¬ 
luble white powder. 

j • 9 »■*,♦ 

Davy's Discoveries . 

161. The Galvanic battery became, in the skillful hands of 
Sir H. Davy, the means of effecting the most brilliant discove¬ 
ries. With this instrument, he ascertained the compound nature 
of the alkalies and earths , a fact which had previously, been only 
suspected. This discovery has introduced a new era in the an¬ 
nals of Chemistry, and added several new metals to the list of 
simple elements. No known compound has been able to resist 
the decomposing power of galvanism ; and it is regarded as the 
strongest proof of the elementary or simple nature of a body, 
when it gives no signs of decomposition on being subjected to 
the influence of this agent. 

162. To account for the decomposing effect of galvanism, it 
is necessary to recur to the principle of electric attraction and 
repulsion. If two particles, united to form a compound mole¬ 
cule, are both brought into the same electrical state , they will ex¬ 
ert a mutual repulsion ; and if this repulsion be more powerful 
than the force of their chemical attraction, they must necessari¬ 
ly separate, and the compound will be destroyed. 

Or, even if they be in opposite states of electricity , since they 
are both within the influence of the battery, that particle which 
has the strongest tendency to become negatively electric, will 
naturally become so by induction, and be attracted to the posi¬ 
tive pole ; and at the same time, a similar change in the opposite 
direction, will take place with the other particle. 

163. Sir H. Davy was led to infer that chemical and electri¬ 
cal attractions are effects of the same cause. Having brought a 
dry acid in contact with a metal, he found that the former be¬ 
came electro-negative ; an alkali, treated in the same manner, be¬ 
came electro-positive ; and when an acid and an alkali, both dry, 
were made to touch each other, electrical excitement w r as pro- 


161. Decompositions effected by Davy. Strong proof of the elemen¬ 
tary nature of a body. 

162. Explanation of the decomposing effect of galvanism. Why com¬ 
pounds are destroyed by electrical repulsion. Why there should be a de¬ 
composition when the particles are in opposite states of electricity 

163. Davy’s experiments to prove the connection between chemical 
and electrical attractions. Electricity of acids and alkalies. A body 
may be electro-positive with one body, and electro-negative with anoth¬ 
er. Why chlorine and oxygen form compounds which are easily de¬ 
composed. 




IMPONDERABLES. 


73 


duced, the acid being negative and the alkali positive. Further¬ 
more, those bodies which exhibit the greatest tendency to chem¬ 
ical combination, are also prone to assume opposite electrical 
states ; and though two bodies, A and B , wdiich, if successively 
brought in contact with C, would each assume the same electri¬ 
cal state, may be in opposite electrical states when in contact 
with each other ; yet if they combine, their compound A B , is 
held together by weak affinities, and is easily decomposed. Ex¬ 
amples of this kind may be found in the instances of chlorine 
and oxygen; each of these bodies is strongly electro-negative, 
when in contact with hydrogen, and each lorms with it, a well- 
defined compound. But chlorine, though electro-negative when 
compared with almost all bodies, is electro-positive with regard 
to oxygen, and may be made to combine with it; yet the com¬ 
pounds formed by chlorine and oxygen, are decomposed with re¬ 
markable facility. 

164. The electro-chemical theory, which all these facts go to 
support, supposes the same electrical excitement to take place 
between atoms in contact with each other, as we have seen to be 
produced by masses ; that the atoms remain in contact, that is to 
say, in combination, in consequence of the electrical attraction 
consequent on this excitement; and that their union ceases, 
whenever, by any cause, they are brought into the same electri¬ 
cal state, or when they are exposed to the action of any third 
body which is more highly excited than either ; for, in the lat¬ 
ter case, the highly excited body will attract the particle which 
is dissimilarly excited, and repel that which is similarly so ; and 
this is what happens in the decomposition of a compound sub¬ 
stance by the galvanic battery. 

165. Following the same course of reasoning which led him 
to the discovery of the alkaline metals*, Sir H. Davy made other 
very useful applications of his theory. Although the metals, 
compared with oxygen, are all electro-positive, yet when com¬ 
pared with each other, as we have seen in the case of zinc and 
copper, they may have opposite natural electric energies ; and 
from experiment, as well as from theory, it is shown, that the 
positive metal will have the strongest tendency to combine with oxy- 

* Sodium, potassium, &c. being metals found in the alkalies, soda, pot¬ 
ash, &c. are termed alkaline metals. 


164. Electro-chemical theory founded upon the preceding facts. 

165. Applications made by Davy of his theory, with respect to the 
electrical attraction of the metals. Why copper is protected from rust 
or oxidation, by zinc or iron ; why iron and steel are protected by zinc. 

7* 



74 


GALVANISM. 


gen. Thus copper is rapidly corroded in acid, or saline solu¬ 
tions ; but in contact with zinc, iron and some other metals, cop¬ 
per becomes electro-negative, and remains bright, while the oth¬ 
er metal is rapidly deoxidized ; this happens, also, in the gal¬ 
vanic battery. By many experiments, Davy found that a slip 
of zinc or iron, would protect from rust 150 times its surface of 
copper, though constantly exposed to the action of salt water ; 
and he proposed to apply this principle to the preservation of the 
copper sheathing of ships. The rusting of fine iron or steel in¬ 
struments, may be effectually prevented by fixing a piece of zinc 
in their handles or elsewhere, so that it shall be always in contact 
with the blade. 

166. The classification of bodies in a system of Chemistry, 
according to their electric energies, has been adopted by many 
eminent Chemists, and though the electro-chemical theory is far 
from being perfect, yet, as it furnishes a convenient system for 
instruction, we shall adopt an arrangement of subjects founded 
upon it. 

167. The relations existing between magnetism and electri¬ 
city, are daily becoming more fully developed. These relations 
present an exceedingly curious subject of philosophical research ; 
and the facts already accumulated, constitute a new branch of 
physical science, under the name of Electro-magnetism. 

168. Hare’s Calorimoter ^or 
mover of heat,) consists of a 
number of square zinc and 
copper plates of any conve¬ 
nient size, alternating with 
each' other in a wooden 
frame. Two rectangular tubs 
accompany the apparatus, one 
containing the liquid acid for 
exciting the electricity, and 
the other to hold water for 
washing the plates. By 
means of an upright cross bar 
with a rope and pulley, the 
frame containing the plates 
’ e at pleasure immersed 
removed from the acid 
: and this facility af- 
great advantages : for 
ascertained that the 
st action of the galvan¬ 
ic battery is at the first in. 

166. System of Chemical classification ; on what to be founded ? 

167. Electro-magnetism. 

168. Hare’s Calorimoter. Deflagrator. 


Fig. 37. 



in, or 
liquid 
fords 
it is 
greate 





























































































IMPONDERABLES. 


75 


stant of immersion; and it is, therefore, important to be able to immerse 
all the plates at once. Besides the effects of the calorimoter in igniting 
wires, during its action much hydrogen is evolved from the liquid, and 
the gas is sometimes inflamed by the great heat produced. (The figure 
at 1, represents the entire instrument ready to be plunged, and at 2, the 
top of the plates.) 

Another instrument invented by Dr. Hare is the Defiagrator ; this is a 
modification of the Galvanic battery. 

Theories of Galvanism. 

169. The principal theories, explanatory of galvanic action 
are, 1st, The electrical theory of Volta ; 2nd, the chemical theo¬ 
ry of Wollaston ; 3d, the electro-chemical theory of Davy. 

The theory of Volta considers the contact of the metals to be 
the only cause of electric excitement; it attributes to the liquid, 
no other agency than that of conveying the electricity by means 
of its conducting power, from one pair of plates to the next, 
and thus enabling it to accumulate at the poles. 

The chemical theory is so called, because it regards the chem¬ 
ical action which goes on in the pile, viz., the oxidation of the 
zinc , as the original disturber of electric equilibrium. This the¬ 
ory, Dr. Wollaston supports by arguments drawn from various 
experiments. It is perfectly true, that the contact of the metals 
will produce electric excitement; but it is also equally true, that 
electricity is developed during chemical action. Furthermore, it 
is observed that the activity of the pile is increased, when, by 
using a more powerful acid, the chemical action is rendered more 
violent. It seems, therefore, reasonable to give the preference to 
the following theory which unites the two. 

3d. Davy’s theory, or the electro-chemical , supposes that the 
electric equilibrium is first disturbed by the contact of the zinc 
and copper plates, and that the excitement is afterwards kept up, 
and increased by the chemical action between the liquid and the 
metal. 

Dr. Hare does not attribute the heating effects of the battery 
to electricity, but supposes the fluid evolved by this machine to 
be a compound of electricity and caloric, in which the propor¬ 
tions of the two constituents vary according to circumstances ; 
thus, in the use of his calorimoter, great heat is excited, while 
the electric tension is very small. 

170. In concluding our observations upon the imponderable 
agents, we will remark, that though we have examined their 
operations and effects , we have not attempted to decide upon their 


169. Three theories of galvanism. Volta’s theory. The chemical 
theory. Electro-chemical theory. Dr. Hare’s opinion respecting the 
heating effects of the battery. 

170. Concluding remarks on the subject of imponderable agents. 



76 


GALVANISM. 


nature; or to determine whether they are substances , or qualities 
of other invisible substances. Such is the intimate connection 
between caloric, light and electricity, that many philosophers 
suppose them all to be modifications of the same power or sub¬ 
stance. We cannot but regard them with awe, as mysterious 
agents, whom the Almighty subjects, in some degree, to our 
will, but of whose essential nature we are ignorant. We know 
that they possess immense force, and though we seem, for many 
purposes, to have them under our control, we are liable at any 
moment to be destroyed by their power. It is the Creator him¬ 
self, only who knows the u hiding of their forces who only 
can restrain, and hold them in combinations so justly and wisely 
modified and balanced, as to uphold and preserve that beautiful 
harmony in the order of Nature and of Providence which he 
has established. 


PART II. 


INORGANIC CHEMISTRY. 

LECTURE VI [. 


CHEMICAL NOMENCLATURE.-AFFINITY. 

171. An important change of subjects now presents itself. 
The bodies we are about to examine, are such as we can either 
see, or handle, or which we can prove to possess weight; they 
are, therefore, known to be matter , and are called ponderable, a term 
which implies having weight. 

172. The study of ponderable bodies naturally divides itself in¬ 
to two parts, called Inorganic and Organic Chemistry. By In¬ 
organic Chemistry is meant the study of the elementary bodies, 
with their combinations, as existing in inorganized matter as 
water, air, earths, minerals, &c. Organic Chemistry treats of the 
chemical constituents of plants and animals. We shall meet in 
Organic Chemistry with no elements not found in inorganic sub¬ 
stances. It is owing to the different proportions , and mode of 
combination , that organic compounds differ in their qualities so 
essentially from compounds that are found in the inorganic king¬ 
dom ; thus the blood of animals and the sap of vegetables, are 
peculiar fluids resulting from the action of a living principle, de¬ 
prived of which, both animals and plants become the prey of the 
chemical and mechanical forces which are constantly in opera¬ 
tion around them. 

173. Before proceeding farther, we will explain the nature of 
certain bodies, to which we shall have frequent occasion to al¬ 
lude. We will then give a brief exposition of the principles and 
rules on which the chemical nomenclature is founded. 


171. Meaning of the term ponderable. 

172. Distinction between Inorganic and Organic Chemistry. The 
same elements enter into the composition of .Organic and Inorganic 
matter. 

173. Preliminary subjects to be discussed. 



78 


INORGANIC CHEMISTRY. 


The great subject of chemical affinity, will next be examined, 
and the laws of chemical combination discussed and explained. 
These are all necessary preliminaries to the consideration of the 
ponderable bodies. Though at first these subjects may seem 
obscure, the mists will gradually break away as we proceed, and 
the science appear in its true and beautiful proportions. Each 
advance we there make, will reveal new and striking evidence of 
the immutable basis on which it rests; and that Chemistry, if 
not itself a divine science, proclaims the divine origin of matter ; 
clearly refuting the absurd idea, that a blind chance, brought the 
material atoms into existence and presides over their combination. 

174. By the term salt , as used in Chemistry, is meant a defin¬ 
ite compound of an acid and a salifiable * base. 

An acid is generally sour, soluble, capable of reddening the 
blue color of violets and of litmus|, and of combining with and 
neutralizing the salifiable bases. But some acids are not soluble 
in water, and therefore do not taste sour nor redden vegetable 
blues ; others do not neutralize the salifiable bases, though they 
combine with them. According to a strict chemical definition of 
the term, an acid is a substance which combines in definite propor¬ 
tions with salifiable bases to form salts. 

175. Salifiable bases are all metullic oxides J except ammonia,|| 
and the vegeto-alkalies.^ All the soluble, salifiable bases, (in¬ 
cluding ammonia, but excluding the vegeto-alkalies,) have an 
acrid taste, and are highly caustic, green the blue of violets, 
restore the blue of litmus when it has been reddened by an acid, 
and combine with acids in definite proportions to form salts. 
These are the properties which constitute an alkali ; and hence 
the salifiable bases which do not possess them all, are not called 
alkalies But there is no proof that the absence of these proper¬ 
ties in certain salifiable, metallic oxides is not owing to insolu¬ 
bility. The insoluble , salifiable bases possess only the last men- 

* Salifiable from the Latin Sal salt, with an English termination, 
means capable of becoming a salt. 

t Litmus is prepared from a lichen, (Lichen roccella ;) it is of a blue 
color, and paper dipped in its infusion furnishes a delicate chemical test. 

t By metallic oxides is meant a compound substance composed of a 
metal and ox y gen. Oxide of iron is oxygen and iron; oxide of gold is 
oxj^gen and gold, &c. It is not to be understood that every metallic 
oxide is a salifiable base ; some, oxides are acids, and some, neither acids 
nor bases. 

|| Ammonia is a compound of two gases, Nitrogen and Hydrogen. 

§ Vegeto-alkalies are compound alkaline bases, obtained in the analy¬ 
sis of Vegetable substance. 

174. Definition of a salt, of an acid. 

175. Salifiable bases. 



NOMENCLATURE. 


79 


tioned and most important of the alkaline properties, that of com¬ 
bination with acids. 

176. Some salts exhibit the properties of neither acid nor 
base, and are called neutral salts ; others are acidulous , which 
property generally arises from an excess of acid, but sometimes 
from the feebleness of the base; others are alkaline, generally 
from an additional quantity of the base, but sometimes from the 
weak neutralizing power of the acid. Acidulous salts are fre¬ 
quently called super salts, as super tartrate of potassa, &c.; and 
salts exhibiting the properties of the base are sometimes denom¬ 
inated sub- salts, as sub-carbonate of soda. 

Some salts are soluble, others are not so ; all soluble salts have 
taste, and most frequently a disagreeable one ; none of them have 
odor, but the carbonate of ammonia. Some are colored, others 
colorless, and many of them are capable of crystallization. 

Chemical Nomenclature. 

177. It is readily conceivable, that if every substance exam¬ 
ined by the Chemist, were to be named as caprice or fancy might 
suggest, the memory would be capable of retaining but a very 
small number of the names. To obviate so great an inconveni¬ 
ence, a systematic nomenclature, suggested by Lavoisier, Guy¬ 
ton Morveau, and other French Chemists, about the year 1784, 
has been adopted. It is founded on the principle that the name 
of every substance ought to express its composition if a com¬ 
pound, or some striking property if it be a simple body. The 
simple bodies already known, were permitted to retain their es¬ 
tablished names. 

178. In conformity with these principles, oxygen was named 
from two Greek words, implying a generator of acids , under the 
erroneous belief that it is the only producer of acidity. Hydro¬ 
gen literally means the generator of water. Chlorine signifies a 
green substance, as its name implies, &c. &c. &c. The combi¬ 
nations of simple electro-negative substances with other bodies 
are designated by names ending in ide, as oxides , chlorides , io¬ 
dides and bromides. And where these elements form more than 
one combination with the same body, the different compounds 
are distinguished by prefixing Greek ordinals, marking the rel- 

176. Neutral, super and sub-salts. Soluble salts. Various properties 
of salts. 

177. On what principle is the systematic nomenclature founded ? 

178. Origin of the names of some of the elementary bodies. Names 
given to the combinations of simple electro-negative bodies with other 
bodies. Names of combustions of simple combustible bodies with each 
other. 



80 


INORGANIC CHEMISTRY. 


ative proportions of the Electro-negative ingredient; as prot-ox- 
ide of iron, deaJo-chloride of mercury, tetVo-iodide &c., the high¬ 
est compound being called per*- oxide, joer-chloride, &c. meaning 
that the body has been oxidized, &c. through all the stages possi¬ 
ble. The termination uret , is given to names of combinations of 
simple combustible bodies with each other : as sulphuret of Lead , 
phosphuret of carbon, carburet of iron , &c. 

179. Where but one acid is formed by the union of the same 
elements its name terminates in ic ; as muriatic acid , carbonic 
acid, &c. But it frequently happens that oxygen, by uniting in 
different proportions with the same body, forms several distinct 
acids ; when this is the case, the acid highest in oxidation has 
the final ic and a lower one the termination ous ; and the inter¬ 
mediate degrees of oxidation are expressed by the prefix hypo , 
signifying under. Thus sulphur forms with oxygen the four fol¬ 
lowing acids ; sulphuric , hypo-sulphuric\, sulphurous and hypo- 
sulphurous acids. 

180. The termination ate , expresses the salt of an acid end¬ 
ing in ic ; and the termination ite the salt of an acid ending in 
ous. Thus we have sulphates, and hypo-sulphates, sulphites and 
hypo-sulphites. 

It has been stated, (§176), that the same acid and base, by 
combining in different proportions may form different salts : and 
that the name super- salt is given to those containing more acid, 
and that of sub- salt to those containing more base than the neu¬ 
tral salt. These names are objectionable because they do not ex¬ 
press the proportions by which either ingredient is in excess ; so 
that different sopcr-salts, or different sub-salts of the same base 
and acid are confounded under one general appellation. 

To obviate this inconvenience, the number of equivalents or 
combining proportions of acid in the super-salts is denoted by 
Latin prefixes ; while Greek numerals point out the proportions 
of base in the sub-salts. 

Thus we have the neutral oxalate , the binoxalate , and the quad- 
roxalate of potassa , the first of which contains one atom, the sec¬ 
ond two , and the last four atoms of oxalic acid to each atom of 
base. Again, among sub-salts are the neutral acetate, the di-ac¬ 
etate, and the tris -acetate of lead ; the first being composed of 
one equivalent of acid, and one of base, the second of one of 

* From the Latin per signifying through. 

t Hypo signifies under or below, thus hypo sulphuric acid means one 
which has a lower degree of oxidation than sulphuric acid. 

179. Nomenclature of acids. 

180. Nomenclature of salts. More definite mode of describing salts 
than by the terms super and swi-salts. 



NOMENCLATURE. 


81 


acid and two of base, and the last, of one of acid to three of 
base ; and if there were a fourth compound consisting of one of 
acid to four of base, it would be the tetra acetate of lead. 

181. The proportion of terms proto, deuto , trito, per, &c., when 
placed before the generic names of salts, refer not to the propor¬ 
tions of acid and base they contain, but to the degree of oxida¬ 
tion of the base. Thus the proto-sulphate of iron means the 
sulphate of the protoxide of iron, the per-sulphate of copper is 
the sulphate of the per-oxide of copper, &c. 

182. Different salts may sometimes combine and produce 
what are called triple salts , or, more properly double salts . A 
double salt may consist of two acids and one base, of two acids 
and two bases, or, what is by far the most common, of one acid 
and two bases. The latter are bi-basic salts ; such are the double 
tartrate of potassa and soda , which is the tartrate of potassa unit¬ 
ed with the tartrate of soda, commonly called Rochelle salt; 
tartar emetic is the double tartrate of antimony and potassa. Some¬ 
times, the name of one base precedes, and that of the other, fol¬ 
lows the generic name ; as the ammonic-sulphate of copper , 
which is the double sulphate of copper and ammonia. 

183. Acids which are formed by the union of oxygen with 
another simple substance, are called oxacids , those composed ol 
hydrogen and a radical are hydracids ; thus the proper chemical 
name of muriatic acid, (which consists of hydrogen and chlo¬ 
rine,) is hydro-chloric acid ; hydrogen and iodine form hydriodic 
acid; and hydrogen with bromine constitutes hydro-bromic acid. 


Specific Gravity. 

184. The physical characters of bodies are often valuable aids in dis¬ 
criminating between different substances. Some of these characters, as 
the color, may be considerably affected by the presence of foreign sub¬ 
stances. Among the most constant and valuable is specific gravity. 

The specific gravity of a substance is its weight, compared with an 
equal bulk of some other substance, taken as the standard of unity. 
This standard for solids and liquids is water, and for aeriform bodies, at¬ 
mospheric air. If we weigh a solid body in air, and again weigh it sus¬ 
pended in water, it will be found, in the last instance, to weigh less 
than in the first; and the loss of weight is ascertained to be the exact 
weight of an equal volume of the fluid displaced : thus it is an axiom in 


181. The prefixes proto, deuto, &c., when placed before the generic 
name of the salts. 

182. Double salts. 

183. Oxacids and hydracids. 

184. Definition of the term specific gravity. Standard of specific 
gravity for solids and liquids. Mode of finding the specific gravity of a 
solid not soluble in water. 

8 



82 


INORGANIC CHEMISTRY. 


hydrostatics, that the weight which a body loses when immersed in a fluid 
is equal to that of an equal bulk of that fluid. 

If, theiefore, a solid body be not soluble in water, we take its exact 
weight in the usual manner; then weigh it suspended in pure water, and 
subtract this weight from the former,—the difference is the weight of a 
bulk of water equal to the solid. We now have the proportion,as the 
difference just mentioned, is to the weight of the solid in air, so is one, 
(the assumed specific gravity of water,) to a fourth proportional, which 
is the specific gravity required. 

185. The instrument used to determine the specific gravity of bodies 
is called the hydrostatic balance. B C D is a balance ; E a glass vessel 
containing water. Suppose that we wish to determine the specific grav¬ 
ity of sulphur ; we suspend a small bit by a hair or fine thread of silk 
from the balance at C : we find that it weighs in the air 12 grains. We 
then immerse it in the water as represented in the figure, and find it 
has lost weight: we add to the scale C, a sufficient number of grains 


Fig. 38. 



to cause it to balance the scale D. Suppose these grains are 6, this is 
then the weight lost by the immersion. We then say as 6, the differ¬ 
ence between the bit of sulphur in water, and in air, is to 12, the weight 
in air so is 1, the assumed specific gravity of water, to 2, the specific 
gravity required ; or thus, as 6 : 12 :: 1 : 2. 

186. If the solid, whose speciffc gravity you wish to find, is soluble 


185. Hydrostatic balance, 

186. Mode of finding the specific gravity of a solid which is soluble 
in water. 






























SPECIFIC GRAVITY. 


S3 


in water but not in alcohol, ascertain first the specific gravity of alco¬ 
hol and then take that of the solid with regard to alcohol just as before 
described. If the solid be soluble also in alcohol, any liquid in which it 
is insoluble maybe substituted. 

187. To find the specific gravity of a liquid, fill any convenient phial 
with distilled water and ascertain its exact weight, taking care that it 
shall be perfectly d^ on the outside ; then pouring out the water and 
drying the phial carefully, fill it with the liquid under examination and 
weigh it; the last weight will be to the former as 1, is to the specific 
gravity of the liquid. 

Another mode consists in ascertaining the comparative heights of the 
columns of the two fluids which are necessary to support a given column 
of mercury ; the specific gravities of the liquids are in the inverse ratio 
of their respective columns. 

188. To ascertain the specific gravity of gas, it is first necessary to 
know that of atmospheric air. Sir George Shuckburgh states that 100 
cubic inches of air weigh 30.5 grains and this estimate is generally adopt¬ 
ed as correct. 

Having exhausted a thin glass flask by means of the air pump, it is to 
be filled with the gas in question, and weighed. The proportion is ex¬ 
actly as in the case of liquids substituting the weight of an equal bulk 
of air for that of water. 

This is an exceedingly nice operation; and the following circumstan¬ 
ces must be strictly observed,— 

1st. The gas must be perfectly pure. 

2nd. It must be absolutely dry. Moist gas is dried by passing it over 
pieces of chloride of calcium, or of pure potassa, which absorb the moist¬ 
ure. 

3d. The influence of atmospheric pressure, in decreasing the bulk, 
consequently increasing the specific gravity of gases must be taken into 
account. The average height of the barometric column is 30 inches; 
if it should be more or less during the experiment, the apparent sp. gr. 
will be more or less than the true one. 

4th. As the bulk of a gas depends also on the temperature, if the ther¬ 
mometers of Fahrenheit do not stand during the experiment at 60°, the 
standard or mean temperature, a correction must be made upon the prin¬ 
ciple that gases expand by 1-180, of the bulk they occupied at 32“, for 
each additional degree of Fahrenheit’s thermometer. 

189. It is a remarkable characteristic of chemical union that 
the compounds resulting from it, for the the most part possess 
neither the external characters, nor the internal properties of 
their constituents. Thus, it is impossible to foretel from a 
knowledge of any two substances what may be the nature of the 
body which will be formed by their combination. Chemistry 
requires, therefore, experiments or trials, in order to prove by 
every possible method not only the nature of simple bodies, but 


187. To find the specific gravity of a liquid. 

188. To find the specific gravity of gas. Circumstances to be regard¬ 
ed in weighing gases. 

189. Characteristics of chemical union. Why experiments are neces¬ 
sary in chemistry. 



84 


INORGANIC CHEMISTRY. 


the effects which may be produced by their union with each 
other. 


AFFINITY. 

Affinity , or chemical attraction, will be considered under the 
following heads : Simple, Elective, and double Elective Affinity. 

Simple Affinity. 

191. Simple Affinity is the union of substances without caus¬ 
ing any decomposition ; thus sulphuric acid added to soda, forms 
sulphate of soda, and potassa forms soap with oil and water. In 
these cases, no previous combinations are broken up. 

192. Experiments to show that affinity produces compounds whose 
properties differ, essentially, from those of the components. 

Experiment Is?. Common liquid muriatic add, consists of a gas 
dissolved in water; it is very sour, inflames the skin and chang¬ 
es to red, the blue color of vegetable infusions; these proper¬ 
ties are derived from the gas it contains. 

Liquid ammonia , or spirits of hartshorn, is also a solution of a 
gas in water ; it possesses a well known pungent odor, acts as a 
caustic on the skin, and changes blue vegetable infusions to 
green. If drops of each of these liquids be spread with a feath¬ 
er on the bottoms of two glass vessels, the gases will escape 
from the water and rise. Now invert one of the vessels over 
the other, placing their mouths together, and they will both be¬ 
come filled with dense white vapor. After standing in the cold 
for a time, the vapor will condense on the sides of the vessel, 
forming a white crust, which has none of the characteristics of 
either of the two constituents, and which, though solid, is com¬ 
posed of two gases ; this is the common sal ammoniac, or mu¬ 
riate of ammonia. 

Experiment 2nd. Pour diluted nitric acid, or aqua fortis, on some 
fragments of copper, a violent action, attended with much heat, 
will take place, suffocating red fumes will rise,* and at last there 
will remain a bright blue liquid, which is a solution of nitrate of 
copper, and contains both of the materials used. 

Experiment 3d. Pour nitric acid, slightly diluted, on powdered 

* These fumes are very poisonous, if inhaled by breathing, and should 
be avoided. 


190. Different kinds of affinity. 

191. Simple affinity. 

192. Experiments to illustrate simple affinity. 



AFFINITY. 


85 


tin. As in the last experiment, red fumes will be given off, and 
the tin will be converted into a white powder, which is a com¬ 
pound of oxygen and tin, oxide of tin. 

Experiment 4th. Pour strong sulphuric acid , into a strong solu¬ 
tion of muriate of lime. The two transparent liquids will be con¬ 
verted almost instantly, with great evolution of heat, into a white 
solid, the sulphate of lime. 

Experiment 5th. Caustic soda is very acrid to the taste and 
blisters the tongue. Dissolve some of this in muriatic acid , and 
boil to dryness ; and the result is common salt, muriate of soda. 

193. These examples abundantly show how complete is the 
change of properties resulting from the chemical union of bodies ; 
affecting their color, taste, odor and temperature ; causing them 
to pass from the solid, to the liquid or gaseous state, and vice versa; 
and producing as great an alteration of their chemical, as of their 
physical characters ; so that we find it is impossible to judge be¬ 
forehand, from the properties of two bodies, what will be those 
of the compound they may form. 

194. In most instances of chemical action, the temperature is 
altered. Sometimes, as in case where the action is attended 
with the liquefaction of a solid, or the vaporization of a liquid, 
the temperature falls. But, in most cases, an elevation of tem¬ 
perature takes place, as is exemplified in the foregoing experi¬ 
ments 2, 3 and 4, and in the following. 

Experiment. Mix a portion of strong sulphuric acid, with one 
fourth of its weight of water ; the liquid will become heated 
above the boiling point of water. 

In this, and many similar instances, the rise of temperature 
is attributable to a condensation and consequent diminution of 
volume, in the course of which some of the caloric of expan¬ 
sion is given off, and accordingly the above mixture will be 
found to measure less than the two liquids did before mixing 
them. 

195. Change of properties affords a criterion by which we are 
to know, in general, whether chemical combination, or only a 
mere mechanical mixture has taken place. 

There are a few cases in which the properties of one of the constituents 
are apparent in the compound. For example, the mixture of sulphuric 
acid and water, (see Ex. § 194,) still exhibits all the properties of sul¬ 
phuric acid and will continue to do so, even when very largely diluted 
with water ; yet there can be no doubt that a chemical union exists be¬ 
tween its two ingredients. 


193. General truths established by the preceding experiments. 

194 Temperature affected by chemical action. 

195. What fact is supposed to be proved by this change of properties ? 
Cases in which this change does not take place. 

8* 



86 


INORGANIC CHEMISTRY. 


Again, if common salt be put into water, it will begin to dissolve, and 
will in a short time, disappear entirely. The disappearance of the salt, 
is owing to its uniting chemically with the water, yet every drop of the 
liquid exhibits the properties of salt. In these cases, the combining en¬ 
ergy of the bodies concerned is but small, and their union can be over¬ 
come by means proportion ably simple. 

196. It is an important law of affinity, that a substance is 
very differently attracted by other substances ; so that, though 
it may have a very strong affinity for one, it will have a very weak 
one for another ; and in some cases, there may be no affinity 
whatever, between two bodies ; thus chalk and water may re¬ 
main together for any length of time, without combining. Some¬ 
times, in such cases, the union may be effected by the intervention 
of a third body, which may form, with one of the first, a com¬ 
pound capable of uniting with the other. For example, a com¬ 
mon flint will not dissolve in water ; but if it be mixed with 
common pearlash, ( carbonate of potassa ,) and heated red hot 
in a crucible, a compound is formed which dissolves readily in 
water. 


Single Elective Affinity. 

197. In elective affinity, there is an election or choice, and, of 
course, an exclusion. If we present to a compound already formed, 
another body, which has for one of the constituents of the com¬ 
pound, a greater affinity than they have for each other, the old 
compound will be broken up, and a new one formed, while one 
of the constituents of the old compound, will be left disengaged ; 
thus, baryta has considerable affinity for muriatic acid , and the 
two unite, forming muriate of baryta ; but, if sulphuric acid be 
poured into a solution of muriate of baryta a white powder will be 
formed, and fall to the bottom of the vessel. This white powder 
is a compound of sulphuric acid and baryta, sulphate of baryta ; 
and it is formed, because baryta has a greater affinity for sul¬ 
phuric, than for muriatic acid. 

Experiment ls£. Camphor combines with alcohol, and forms a trans¬ 
parent solution ; but on adding water, for which the alcohol has a greater 
affinity than for camphor, the latter is precipitated in the form of white 
scales. 


196. Different degrees of affinity. 

197. What is implied by the term elective affinity ? Example. 
Experiment 1st. 



AFFINITY. 


87 


The following diagram illustrates this change : 

Spirit and water. 

Solution C Spirit } 

of < and > Water. 

Camphor. ( Camphor 3 

-_ v - 

Camphor. 

r The compound solution of camphor is represented at the left of the dia¬ 
gram. The interior of the figure, shows the constituent principles, (spirit 
and camphor,) and at the right is the substance added,(water,) to produce a 
decomposition. Above and below are the results of this decomposition. 
The lower horizontal line is turned downwards in the center, to desig¬ 
nate that the camphor is precipitated; while the upper line, being- 
straight, shows that the new compound, water and spirit, remains in 
solution. 

Experiment 2nd. If sulphuric acid be added to carbonate of 
lime, sulphate of lime will be precipitated, and carbonic acid dis¬ 
engaged in the form of gas. 

198. Precipitation is of great use in Chemistry. It separates 
solids from solutions in which they may be held, and reduces 
the molecules of a body to a state of separation, which cannot 
be attained by any mechanical division. Thus precipitates 
possess their medical activity. They are also in a state favora¬ 
ble for entering into new combinations. For example, silex 
pulverized as fine as possible, may be boiled with liquid potassa 
without dissolving ; but when silex is precipitated from a chemi¬ 
cal solution, it not only dissolves readily in solution of potassa but 
yields to the action of some of the acids. 

Double Elective , or Complex Affinity. 

199. This takes place when two compound bodies, on being 
brought together, exchange their bases, and form new combina¬ 
tions. 

We will here compare the three kinds of chemical affinity : 

1st. Simple Affinity. Let the simple substance, A, be present¬ 
ed to the simple substance, B, if there is an affinity, they will 
combine and form a new compound. 

2nd. Single Elective Affinity. Let a simple substance, A, be 
presented to a compound one B C, and if A, have a stronger affin- 


Experiment 2nd. 

198. Precipitates. 

199. When Double Elective Affinity takes place. Examples of the 
three kinds of affinity. 







88 


INORGANIC CHEMISTRY. 


ity for B than C has, the compound, B C, will be decomposed, 
and a new compound, A B, will be formed. 

3d. Complex , or Double Elective Affinity. If a compound, 
A B, be presented to another compound, C D, the old com¬ 
pounds may be broken up, and A, uniting with D, leaves B, 
to unite with C, forming the two new compounds, A C, and 
D B. 

200. Thus it will be seen, that in single elective affinity, 
three substances are present, and tivo affinities in action ; while 
in complex affinity, four substances are present, and four affinities 
in action. 

201. Experiment. Add to lime water a solution of sulphate 
of soda ; there is no decomposition, because the sulphuric acid 
of the sulphate, has a stronger affinity for soda, than for lime. 
If, instead of lime water, we use muriatic acid , there is still no 
decomposition, because the soda, (of the sulphate of soda,) has 
a stronger affinity for sulphuric, than for muriatic acid. But 
let us take a compound of muriatic acid and lime, ( muriate of 
lime) and mix this with the sulphate of soda , and a double de¬ 
composition will take place. The lime leaving the muriatic 
acid, is attracted to the sulphuric acid, while the soda being 
disengaged, unites with the muriatic acid. The tumbler which 
at first contained a liquid mixture of muriate of lime, and sul¬ 
phate of soda, now presents you with a solid precipitate, which 
is the sulphate of lime , (plaster of Paris,) over this solid, stands a 
solution of muriate of soda, or common salt, which is at once 
recognised by its taste. 

This experiment may be illustrated by the following diagram 
Muriate of Soda 


Sulphate f Soda Muriatic acid } Muriate 

of < and and > of 

Soda. £ Sulphuric acid. Lime. ) Lime. 

Sulphate of Lime. 

The original compounds appear on the right and left, without the 
brackets, while their constituent principles are near them, within the 
brackets. The new products are above and below the horizontal lines. 
The upper line being straight, indicates that the muriate of soda remains 
in solution, and the dip of the lower line, indicates that the sulphate of 
lime is precipitated. 

202. We here perceive a conflict of two series of attractions: 1st, those 

200. Difference between single elective affinity, and complex affinity. 

201. Experiment to shew the effects of complex affinity. 

202. Quiescent and divellent affinities. In what case only double de¬ 
composition can take place. How illustrated by the last experiment ? 









AFFINITY. 


89 


which tend to preserve the original compounds,and 2nd,those which tend to 
destroy those compounds, and to form new ones; the former are termed 
quiescent affinities, the latter divellent affinities. Double decomposition 
can take place, only when the divellent affinities are greater than the 
quiescent. Taking for example, the substances used in our last experi¬ 


ment, the affinities may be stated in numbers, thus. 

The attraction oflime for muriatic acid, .... 104 

Of soda for sulphuric acid,.78 

Quiescent affinities, ..... 182 

Attraction of soda for muriatic acid,.115 

Oflime for sulphuric acid,.71 

Divellent affinities,.186 


The original compounds are then held together by a force equal to 182, 
while the force which tends to draw these apart, and to form new com¬ 
pounds, is equivalent to 186, the latter, therefore, or the divellent affinity 
being the greater, overcomes the former or the quiescent affinity. 

203. Bergmann, of Sweden, first taught the doctrine of elective attrac¬ 
tion. So much was he delighted with this Wonderful law of nature,that 
he seemed not to observe how much affinity is modified by peculiar cir¬ 
cumstances. Succeeding Chemists following his steps, seemed also to 
consider affinity as absolute and independent in its operations. Berthol- 
let, a French Chemist of the present age, advanced some new opinions 
upon this subject. He considered affinity as a mode of attraction, differ¬ 
ing from gravitation only,in the subject upon which it operates, and that, 
in this respect, there is no real distinction between Chemistry and Natur¬ 
al Philosophy. Thus, according to the principles of Newton, the quan¬ 
tity of matter, must have an influence upon combination; and it is, 
therefore, by Berthollet, laid down as an axiom, that “ affinity, is mani¬ 
fested by quantity of matter, or that the chemical action of a body, is 
exerted in the ratio of its affinity, and quantity of matter.” It follows 
from this doctrine, that quantity of matter may compensate for feeble¬ 
ness of affinity. Its supporters, not content with showing, what every 
Chemist must admit, that chemical action is, in a degree , influenced by 
quantity of matter , &c., endeavoured to prove that there is, in fact, no 
such law in nature as affinity ; but that decompositions are caused by 
the circumstances that merely go to modify affinity. Sir Humphrey 
Davy opposed the innovations, of Berthollet, and showed that in many 
respects, his doctrine was false. 

The enlightened Chemist unites himselfto no leader, to take for grant¬ 
ed all his opinions, and reject all which he does not approve. Even the 
young student, whose mind is unclouded by prejudice, is more likely to 
form correct opinions, upon the phenomena of nature, than that partial 
philosopher who has so long contemplated an object in one particular 


203. Errors of Bergmann and others with respect to the unlimited 
power of elective attraction. Opinions of Berthollet. Erroneous con¬ 
clusions of Berthollet and the supporters of his doctrine. Their innova¬ 
tions opposed by Davy. 




90 


INORGANIC CHEMISTRY. 


light, that he can see it in no other; or, who, delighted with some dis¬ 
covery of his own, regards the whole fabric of science of less magnitude, 
than the one atom which lie has added to it. 


LECTURE IX. 

SUBJECT OF AFFINITY CONT1NUED.-LAWS OF COMBINATION.— 
THEORIES OF ATOMS AND OF VOLUMES. 

Causes which modify Chemical Affinity . 

204. Chemical affinity is so governed by fixed and immutable 
laws, that under the same circumstances , its effects will always 
be uniform, and although disturbing causes do often influence 
its operation, and modify its results, yet this no more disproves 
the existence of those laws, than the fact, that a body does not 
fall to the earth when suspended by a cord, disproves the exist¬ 
ence of the laws of gravity. In either case, the force of attrac¬ 
tion is all the time acting, but is counteracted by opposing forces. 
Indeed, we are acquainted with most of the disturbing causes, 
and with their mode of acting ; and, in many cases, are able, 
from this knowledge, to predict what will be the variation from 
ordinary results. 

205. The most important of the causes which modify affinity, are, co¬ 
hesion, elasticity, quantity of matter, gravity and the action of the impon¬ 
derables. 

206. Cohesion forbids freedom of motion among the particles, and pre¬ 
vents them from coming into that contiguity which is essential to 
chemical action. Two substances in the solid state, seldom act on each 
other, although they may have a strong tendency to do so. The most 
favorable state for combination, is the liquid one ; the particles have per¬ 
fect freedom of motion, and if they do not combine, when in this condi¬ 
tion, it is fairly inferred, that they have no affinity for each other. 

Caloric is frequently used to overcome cohesion, and to bring bodies 
into the liquid state, by fusing them ; thus sand, powdered glass, or flint, 
have no action with pearlash when solid, but if melted together, they 
combine and form a new compound. 


204. How far the laws of chemical affinity are fixed. The existence 
of these laws not disproved by a variation under peculiar circumstances. 

205. Some of the causes which modify affinity. 

206. Effect of cohesion upon chemical affinity. State most favorable 
for combinaton. Modes of overcoming cohesion, for purposes of chemi¬ 
cal combination. By caloric. 




AFFINITY. 


91 


207. Another mode of effecting the same object, is by solution. When 
a solid disappears in a liquid, without disturbing its transparency, it is 
6aid to dissolve , and the act of dissolving, is called solution ; the liquid 
containing the dissolved body, is also called solution. When the body 
dissolved has changed its nature, and cannot be obtained in its original 
state by evaporation, it is said to be in a state of dissolution ; thus, mer¬ 
cury dissolves in nitric acid, but when the fluid particles are evaporated, 
we do not obtain mercury again, but the nitrate of mercury. The com¬ 
bination of the mercury and nitric acid, is an example of strong chemical 
affinity, the nitrate of mercury having no resemblance to either of its 
constituent parts. On the contrary after evaporating a solution of com¬ 
mon salt, we have the same substance as we dissolved. 

208. A solution , though transparent, need not necessarily be colorless. 
For example, blue vitriol gives a blue solution, which is yet transparent; 
but the color of ink is occasioned by very minute particles of black, 
solid matter, mechanically siispcnded , not dissolved in the liquid. 

Experiment. Add to common ink, some drops of nitric acid ; the ink 
becomes colorless; add a little potash in solution, and the ink is again 
black. This experiment maybe thus explained :—the coloring principle 
of the ink, which is a combination of gallic acid and iron , called the 
gallate of iron, is mechanically suspended in the liquid. When nitric 
acid is introduced, the iron having a greater affinity for it than for gallic 
acid, combines with it, forming nitrate of iron, and the coloring principle 
being now decomposed, the liquid is no longer black. On adding pot¬ 
ash, the nitric acid withdraws itself from the iron and unites with the 
potash. The iron being now left disengaged, returns to the gallic acid, 
and the coloring principle, gallate of iron, manifests its existence by the 
blackness of the liquid in which it is suspended. 

209. The property of dissolving, called solubility, is possessed by some 
bodies, in a much greater degree than by others. A body may be soluble 
in one menstruum ,* and not in another; almost any liquid, may for 
some particular purposes, be used as a solvent, but the most common sol¬ 
vents are water and alcohol. 

210. When a soluble body is put into its menstruum, it goes on dissolv¬ 
ing till a certain quantity has disappeared, after which the liquid can 
dissolve no more of the same body ; it is then said to be saturated, and 
the solution so obtained, is a saturated solution. A solution saturated 
with one body, may still dissolve another. 

The point of saturation of the same solid and solvent, varies 
with the temperature ; in general, the quantity dissolved is in¬ 
creased by raising the temperature. 

211. Some bodies, of which common salt is an example, are no more 
soluble in hot, than in cold water; and there are a few, as lime, magne¬ 
sia, &.C., which are even less so. 

* A menstruum, signifies a solvent. 


207. Bodies rendered liquids by solution. Difference between a solu- 
tion and a dissolution. 

208. The coloring principle in ink not in solution. Experiment. 

209. Different degrees of solubility. 

210. A saturated solution. When saturation takes place. Effect of 
temperature in varying the point of saturation. 

211. Some bodies not more soluble in hot, than cold water. 




92 


INORGANIC CHEMISTRY. 


B12. Neutralization is the mutual destruction, or change of properties, 
which sometimes takes place when two substances combine in certain 
proportions. 

213. It might be supposed that the solubilities of different bodies, were 
in direct proportion to their affinities for the solvent; but this is not the 
case. Two bodies of equal affinities for water, may be differently af¬ 
fected by cohesion ; and, as cohesion is an obstacle to the operation of 
affinity, that will be least soluble which has most cohesion. The boiling 
point of a saturated solution is at present the standard of comparison; 
for as the affinity of the dissolved body for the solvent, must necessarily 
oppose the escape of the latter in vapor, the boiling point will be higher 
as the affinity is greater. Accordingly, all saline solutions boil with 
more difficulty than the solvent alone. Sea water, for instance, has a 
higher boiling point than fresh water; but, by boiling it in distillatory 
vessels, the water may be collected in a pure state, and, the salts will be 
left behind in the vessel. 

214. Bodies in solution, may, generally, be obtained again in the solid 
state, by evaporating the solvent; for the volatility of the latter and the 
cohesive attraction of the dissolved body, are more than sufficient to 
counteract affinity. 

Evaporation is usually performed in open, shallow vessels, placed over 
a sand bath and kept moderately warm. When the operation is slowly, 
and uniformly conducted, the solid usually separates in the form of regu¬ 
lar, geometrical figures called crystals. The process of the formation is 
called crystalization. When the evaporation has been carried far enough 
for crystalization to take place, the fact may be known by the solution 
becoming covered with a film or pellicle. Another test, is, to place a 
few drops of the solution on the cold surface of glass or some other pol¬ 
ished substance, if, in such case, a solid is deposited, the point of 
crystalization has been reached. The evaporating vessel should then be 
removed, and set aside in some secure, dry place to cool. 

215. The cohesion of insoluble bodies, may be overcome by fusion and 
vaporising ; thus, brimstone, on being subjected to heat, passes first into 
a state of vapor, and then condenses into the flour of sulphur , which, 
when examined with a microscope is found to consist of small, crystaline 
grains. Bismuth and some other metals may be crystalized in the same 
manner. 

216. In opposing caloric to cohesion, in order to promote affinity we 
must not go so far as to bring bodies into the state of vapor ; for then 
their elasticity , will tend to remove the particles from the sphere of their 
action upon each other. Sometimes indeed, two gases or vapors unite ; 
but the aeriform state is generally unfavorable to combination ; indeed, a 
compound of a fixed and a volatile body may be generally decomposed 
by heat, which increases the elasticity of the latter, as, when limstone, 
(carbonate of lime,) is heated strongly, the gaseous, carbonic acid flies 
off, and quicklime remains. Strong pressure, by bringing the particles 
nearer to each other, sometimes causes two gaseous bodies to unite. 


212. Neutralization. 

213. Solubility not always in proportion to affinity. Effect of cohesion 
with respect to solubility. 

214. Evaporation. Formation of crystals. Effect of a rapid evapora¬ 
tion upon the crystals. Various crystaline forms. 

215. How may the cohesion of insoluble bodies be destroyed? 

216 Effect of the elasticity of vapors. 



AFFINITY. 


93 


When one of the the gases to be combined is inflammable, the union may 
be effected by setting fire to the mixture, or by the electric spark ; in 
these cases, there is commonly a violent explosion, and it should only be 
done in strong vessels. 

217. Experiment to show the effects of cohesion and elasticity on Chemi¬ 
cal Affinity. 

Heat, as we have seen, (§ 216,) decomposes carbonate of lime; but 
no degree of heat has yet been able to decompose carbonate of potassa ; 
this circumstance would lead us to infer, that the affinity of potassa for 
carbonic acid is greater than that of lime ; but, 

Experiment 1st. If limewater, ( solution of lime ,) be poured into solu¬ 
tion of carbonate of potassa , the insoluble carbonate of lime will fall as a 
white precipitate, and the potassa will remain in solution. This would 
seem to show that the affinity of lime for carbonic acid , is greater than 
that of potassa. But, in this case, it is supposed that the cohesion of the 
carbonate of lime, co-operating with the affinity of lime for the gaseous 
carbonic acid , effects the decomposition in opposition to the real order of 
affinities. 

Experiment 2nd. If solutions of muriate of lime and carbonate of am¬ 
monia be mixed, there will be a double decomposition; carbonate of lime 
will be precipitated, and muriate of ammonia will remain in solution. 

Experiment 3 d. Mix muriate of ammonia and carbonate of lime in the 
solid and dry state, place the mixture in a long necked vessel, and apply 
heat to it, the decomposition will now be the reverse of that which takes 
place in the preceding experiment. Carbonate of ammonia will rise in 
vapor, and be condensed in the cool part of the apparatus, while muriate 
of lime will remain in mass at the bottom. 

Each of the acids used in the last two experiments, has affinities for 
both the lime and the ammonia ; the preponderance of one pair of those 
affinities over the other pair, is determined, in Ex. 2, by the cohesion of 
the carbonate of lime, and in Ex. 3, by the volatility of the carbonate of 
ammonia. Generally, when the affinity would admit of the formation of 
several modes of arrangement, one of which would produce an insoluble 
compound, (as the carbonate of lime for example,) that compound would 
be formed in preference to the rest, provided the materials are used in so¬ 
lution. But if the materials be in the dry state, and the operation be 
performed with the aid of heat, elasticity will determine the formation 
of a volatile compound, if such an one be among those which the sub¬ 
stances present are capable of producing. 

218. In respect to quantity of matter as modifying affinity, it may be 
remarked that there are some cases where the use of a large excess of 
one substance, enables us to decompose another contrary to the establish¬ 
ed order of affinities ; the decomposition, however, is seldom complete. 

219. Gravity sometimes interferes with chemical union, by causing 
the heavier body to sink, and thus be removed out of the sphere of the 

217. Circumstance which shows the affinity of potassa for carbonic 
acid, to be greater than that of lime for the same acid. 

Experiment showing that cohesion, combining with a weaker affinity 
may affect decomposition. 

Substances which result from the mixture of solutions of muriate of 
lime and carbonate of ammonia. 

Effect of mixing dry muriate of ammonia and carbonate of lime. Ex¬ 
planation of the changes which take place in experiments 2d and 3d. 

218. Effects of using a large excess of one substance in producing de¬ 
composition. 219. Effects of gravity on chemical action. 

9 



94 


INORGANIC CHEMISTRY. 


others’ action. The effects of gravity are illustrated, in the fusing togeth¬ 
er of two metals of different specific weights ; the alloy being cast into an 
ingot, different portions of it will be found to be unlike in composition, 
the part which was lowest in the mould, will contain a greater pro- 
portion of the heavier metal than the other end. The interference of 
gravity, is obviated by agitation and by stirring. 

220. The effects of heat and galvanism , in producing decomposition 
have been noticed under the heads of the imponderables ; we may far¬ 
ther observe, that the electric spark sometimes decomposes a compound 
gas through which it passes, and sometimes causes the union of two 
gases ; in the latter case, there is usually an explosion. These effects are 
commonly attributed to the heat of the electric fluid. 

LAWS OF CHEMICAL COMBINATION. H 

221. Some substances are capable of uniting in all proportions, 
as when we mix water and alcohol, water and sulphuric acid 
&c. ; though but a drop of one be mixed with a very large quan¬ 
tity of the other, every drop of the resulting mixture will con¬ 
tain proportions of both. 

In such mixtures,, there is, at first, an evolution of heat, sometimes, 
(as in the case of sulphuric acid and water,) very considerable : and 
when the mixture has become cool, its bulk will be less than that of the 
two liquids before mingling them. 

222. Another set of bodies, unite in all proportions up to a 
certain point, beyond which no combination takes place. Exam¬ 
ples of this, are the solutions of salts in water, alcohol, &c., 
when any quantity of the salt not greater than that necessary to 
saturate the solvent, will be dissolved. 

In compounds of these two kinds* the affinities of the components 
are comparatively feeble ; neutralization does not take place, for the 
properties of all the substances concerned are quite apparent; and the 
combination is destroyed by comparatively feeble means, as evaporation 
and the like. But these kinds of compounds are highly useful and im¬ 
portant, as by their means we are enabled to present bodies to each other, 
under the circumstances most favorable to action. 

223. There is a third class of combinations, far more numer¬ 
ous as well as interesting, than the other two. They are those 
in which the proportions of the constituents are regulated by certain 
fixed and invariable laws. In such compounds, the affinities of 
the elements are more energetic, than in the two former classes ; 
the number of combining proportions of the same bodies is 
small, never exceeding six so far as is yet known ; and the ele¬ 
ments neutralize each other. 


220. Effects of the imponderables, especially the electric spark, in 
producing decomposition and combination. 

221. Bodies which unite in indefinite proportions. 

222. Bodies which unite in indefinite proportions up to a certain point. 

223. Combinations where the proportions are always definite. 




LAWS OF CHEMICAL COMBINATION. 


95 


Three Important Laws of Combination. 

224. I. Certain bodies combine in only one proportion. Thus chlo¬ 
rine and hydrogen , unite in the proportions of 36 parts, by weight, 
of the former, to one of the latter, and there is no method known 
of bringing them into combination, in any other proportions; 
for if we mix 36 parts of chlorine gas, with two parts of hy¬ 
drogen, there will, always, be 1 part of hydrogen remaining un¬ 
combined ; or if we mix 72 parts of chlorine and 1 of hydrogen, 
only the proportions first stated will combine, the additional 36 
parts of chlorine remaining in a separate state. 

225. II. When any two elements combine in more than one pro¬ 
portion^ the larger quantities of one are multiples by 2, 3, 4, or 5, 
of the smallest quantity of the other. Oxygen and hydrogen , are 
known to form two compounds with each other ; the first is 
water, which contains 1 part by weight of hydrogen, for every 
8 parts of oxygen. The second compound of oxygen and hy¬ 
drogen is, the deutoxide of hydrogen , which contains 16 parts of 
oxygen, for every one of hydrogen ; here, the proportions of ox¬ 
ygen are twice those of water. 

Nitrogen and oxygen unite in five different proportions, forming 
compounds whose names and composition are as follows : 


Name. 

Parts of Nitrogen. 

Parts of Oxygen. 

Protoxide of Nitrogen, 

contains 

14 for every 

8=8X1 

Deutoxide of “ 

u 

14 “ 

16=8X2 

Hypo-nitrous acid 

it 

14 “ 

24=8X3 

Nitrous acid 

u 

14 “ 

32=8X4 

Nitric acid 

It 

1 1 « 

40=8X5 


No other compounds of the same elements are known : and 
if oxygen and nitrogen be mixed in any other proportions, if any 
combination whatever should ensu6, it would result in the pro¬ 
duction of one or more of the above named b'odies, but of no in¬ 
termediate compound. 

226. To the second laic of multiples , there are a few apparent excep¬ 
tions ; thus iron and oxygen combine in two proportions, which are 28 
parts of iron to 8 oxygen, and 28 iron to 12 oxygen : the first quantity of 
oxygen being to the second as 1 to 1 1-2 

Lead has three oxides, of which the composition is, 


224. 1st. Law of combination. 

225. 2nd. Law of combination or law of multiples. The law of mul¬ 
tiples illustrated in the compounds of nitrogen and oxygen. 

226. Apparent exceptions to the law of multiples. Suppositions on 
which the apparent anomalies in chemical combinations may be ex¬ 
plained. 



96 


INORGANIC CHEMISTRY. 


Protoxide Lead 104 Oxygen 8=8X1 

Deutoxide 104 12=8X1 1*2 

Peroxide 104 16=8X2 

But examples of this kind, are not sufficiently numerous to overthrow 
the general rule ; and they can all be explained by the following hypoth¬ 
eses ; 

1st. We may suppose that the apparent anomaly, results from our not 
being acquainted with all the combinations of the same two bodies. Thus, 
if we should hereafter discover the existence of a compound containing 
28 parts of iron to 4 of oxygen the oxides of iron would then accord 
with the law of multiples, viz., 

Iron. Oxygen. 

1st, oxide 28 (this is the supposed oxide.) 4=4X 1 

2nd, “ 28 8=4X2' 

3d, “ 28 12=4X3 

The same reasoning would apply to the oxides of lead, and to other 
like cases ; and it is in accordance with facts which have already been 
discovered. 

2nd. We may suppose the anomalous compound to be formed, not by 
the direct combination of the two elementary substances, but by the union 
ot two or more of the other compounds of those elements. Thus the first 
and last oxide of lead, might combine as follows, 

Lead. 

Protoxide 104 

Peroxide 104 


producing a compound 208 
where the lead and oxygen are in the exact ratio of 104 to 12, that is, in 
the same ratio as in the compound now called deutoxide of lead. This 
latter may be, therefore, not a distinct oxide, but a compound of two ox¬ 
ides ; which in that case would not furnish an exception to the law of 
multiples. This mode of explanation not only applies to exceptions in 
the third class of combination, (see § 223,) but to the whole of the first 
and second classes; where the apparent great diversity of proportions, 
may be occasioned merely by the combinations of five or six definite 
compounds. 

A third mode of explaining the anomalies will be better understood, 
when we shall have made some remarks on the Atomic Theory. 

227. III. The third law of combination may be stated as fol¬ 
lows : 

The quantities of two bodies which respectively combine with 
a given quantity of a third body, are the precise quantities in 
which the first two combine with each other ; and these are also, 
the quantities in which they would unite with a fourth body. 
Thus 36 parts of chlorine combine with 8 of oxygen , to form 
protoxide of chlorine ; and 36 parts of chlorine combine with 1 of 
hydrogen , to form muriatic acid (called hydro-chloric acid) ; now 
8 of oxygen and 1 of hydrogen are precisely the proportions of 
those two bodies necessary for their combining to form water. 

227. Third law of combination. 


Oxygen. 

16 


24 







LAWS OF CHEMICAL COMBINATION. 


97 


22S. Bodies that unite according to proportional numbers , and 
the numbers expressing the combining proportions, are called 
Primes , Proportionals , or Equivalents. The term equivalent is 
used in several senses, somewhat differing from each other ; thus 
8 parts of oxygen are equivalent to 1 of hydrogen, because they 
saturate the same quantity of chlorine, or of any other body ; and 
those quantities of each, are equivalents , because they are suffi¬ 
cient to neutralize each other If, on mixing particular quanti¬ 
ties of two salts, we find that by double decomposition both are 
wholly destroyed, and exactly replaced by two new salts, the 
quantites we used were equivalents. We speak also of one, two, 
or more equivalents or proportions of a particular body, meaning 
once, twice, &c., its combining quantity. 

229. By analyzing several compounds of a particular body, 
and reducing the numbers expressing the proportions of the con¬ 
stituents to their lowest terms, we establish the combining pro¬ 
portions, or equivalent of that body. And if we do this for a 
great number of different substances, referring, always, the num¬ 
ber determined to some particular standard, we establish a scale 
of chemical equivalents, which greatly facilitates the operations 
of the laboratory. Such a scale has been established by Chem¬ 
ists. It is of no importance what number is taken as the basis 
of the scale, nor what substance is the standard of unity, pro¬ 
vided the proportions be duly observed. In the scale most in use, 
hydroyen is taken as 1, and consequently, 


Oxygen is 

8 

Sulphur “ 

16 

Chlorine “ 

36 

Nitrogen “ 

14 

Potassium u 

40 

Sodium “ 

24* 


* In Dr. Thomson’s scale of chemical equivalents, oxygen is employ¬ 
ed as the basis and is assumed at 1, and therefore hydrogen must be 1-8 
or ,125, sulphur 2, chlorine 4 1-2, &c. Dr. Wollaston, in his scale, calls 
oxygen 10, Berzelius takes it at 100; but in all these scales the same 
proportions are observed. The system of numbers which makes hy¬ 
drogen the unit or 1 is generally preferred, as containing small numbers 
and few fractions. 


228. Meaning of the terms Primes, Proportionals and Equivalents. 
Different senses in which the word equivalent is used. 

229. How may the combining proportions of a body be ascertained ? 
Scale of chemical Equivalents, how established ? What substance is 
taken as the standard of unity in the scale of equivalents most common¬ 
ly used, and what are the combining numbers of some simple bodies in 
relation to this standard ? 

9* 



98 


INORGANIC CHEMISTRY. 


230. The operation of the laws of combination is not con¬ 
fined to the simple substances, it has an equal influence over com¬ 
pound bodies. Thus 40 parts of sulphuric acid, exactly neutral¬ 
ize 48 parts of potassa, and the same quantity of sulphuric acid, 
is also just sufficient for combining with 32 parts of soda : the 
same acid combines with potassa and with soda in other propor¬ 
tions, namely, 80 (=2X40) to 48 and 80 to 32 : so that the law 
of multiples, (see § 225,) likewise governs, these combinations. 
The third law is equally uniform, (§ 227,) for the 48 of potassa 
and 32 of soda, which are equivalent to 40 of sulphuric acid, 
will also neutralize 54 of nitric acid, 37 of muriatic acid, &c. 

231. The combining numbers of compound bodies are found 
by taking the sum of those of their constituents ; thus, sulphu¬ 
ric acid , containing one equivalent of sulphur , 16, and three of 
oxygen , (3 times 8=24,) is 40 ; nitric acid consists of 1 equivalent 
of nitrogen, 14, and 5 of oxygen,(5 times 8=40,)and its equivalent 
number is 54. Muriatic acid is 37, being composed of one pro¬ 
portional of chlorine, (36,) and one of hydrogen, (1 ;) potassa 
contains one combining proportion of potassium, (40) and one 
of oxygen, (8,) and its combining number, therefore, is 48 ; and 
soda is 32, containing sodium , 1 equivalent, (24,) and oxygen , 1 
equivalent, (8.) 

232. From the difference of the combining proportions of the 
acids and alkalies, it follows that their neutralizing powers must 
differ ; for it is evident that the greater this power, the smaller 
must be the quantity necessary to produce the effect. Thus the 
neutralizing power of soda is greater than that of potassa, in the 
inverse ratio of 48, the combining number of the latter, to 32, 
the equivalent of the former. 

233. So well established are the laws of combination, and so 
sure is their operation, that it is very often possible to calculate 
the composition of a body before it is analyzed. And if the re¬ 
sult of an analysis is at variance with these laws, it is a sufficient 
reason for suspecting error in the operation, and for repeating our 
experiments. 

234. The discovery of these laws of combinations, is justly 
considered as one of the most important events in the history of 
Chemistry. It has rescued the science from a chaos of confu- 


230. Compound bodies influenced by the laws of combination, and the 
law of multiples. 

231. How are the combining numbers of compound bodies found ? 

232. Ratio of the neutralizing powers and combining proportions of 
acids and alkalies. 

233. What fact would lead to suspect an error in analysis ? 

234. Discovery of the laws of combination. 



ATOMIC THEORY. 


99 


s>ion,.and established it on the basis of certainty and demonstra¬ 
tion. For this discovery, we are indebted to the genius and in¬ 
dustry of Mr. John Dalton of England. 

Atomic Theory. 

235. Before we proceed to treat of the theoretical explanation of the 
laws of combination, and the atomic theory, it will be necessary to caution 
the learner against confounding the one with the other. The theory of 
Atoms is founded on supposition : and however strong may be the argu¬ 
ments by which it is supported, it may possibly be, hereafter overthrown. 
Not so with the laws of combination. The proof of their existence is 
founded on multitudes of experiments, and is wholly free from specula¬ 
tion ; whether the atomic theory, therefore, be admitted or denied, the 
doctrine of laws of combination remains unshaken. 

236. This ingenious hypothesis was published by Mr. Dalton, to ex¬ 
plain and account for the laws of combination which he discovered. This 
it does, on the assumption that all matter is composed of certain minute 
indivisible particles , aggregated by attraction; that the particles of the 
same kind of matter have the same form, size and iveight: and that they 
are inconceivably smaller than any division of matter , at rohich we can ar¬ 
rive by mechanical operations. The word atom, implying a thing so 
small that it cannot be further cut or divided, is frequently used to de¬ 
signate these supposed indivisible particles* The term molecule, is some 
times used in the same sense. 

237. This theory being granted, the laws of combination, which seem 
inexplicable on any other ground, would follow of course. For since 
chemical combination would take place between the atoms; as, for in¬ 
stance, if a particle of water consists of an atom of oxygen, and an atom 
of hydrogen, and the former atom weighs eight times as much as the lat¬ 
ter, it is clear that any quantity of water must contain these bodies in 
the ratio of 8 to 1. Again, since no addition could be made of either 
constituent in a less quantity than an atom ; that is, if A and B form any 
other compouud than A B, it must be 1 A to 2 B, 1 A to 3 B, &c., or 2 
A to 1 B, 3 A to 1 B, &c. Thus one atom of oxygen to one atom of hy¬ 
drogen, constitutes a particle of water, or protoxide of hydrogen, and two 
atoms of oxygen to one of hydrogen compose a particle of deutoxide of 
hydrogen : and as the oxygen is to the hydrogen, in water, as 8 to 1 ; so 
in the deutoxide of hydrogen, the compounds must be in the ratio of 16 
to 1. Thus the law of multiples, is a necessary consequence of the 
atomic constitution of matter; and this necessity is as peremptory in the 
case of compound particles, as in that of elementary atoms. 

238. The terms Equivalents, combining proportions, &c., of bodies, 
are therefore only other names for the weights of atoms : (not the abso¬ 
lute weights, for of them we do not know, and probably never can know, 
any thing, but their weight, in comparison with the particular body 
which is chosen as the unit. 


235. Distinction between the Laws of combination and the atomic 
theory. 

236. How did Mr. Dalton attempt to explain the laws of combination P 

237. How does the atomic theory explain the laws of combination and 
of multiples ? 

238. By what terms are the weights of atoms designated? 



loo 


INORGANIC CHEMISTRY. 


239. In treating of certain exceptions to the law of multiples, (§226) 
we proposed to defer a third mode of explaining them, till we had shewn 
what was meant by the Atomic Theory. We are now prepared to re¬ 
turn to that subject. 

There is no reason to disbelieve, that combinations may take place, of 
two atoms of one body to 3 of another, 2 to 5, or 3 to 5 ; and since, by 
our theory, half an atom cannot exist, when cases occur of combinations 
in the proportions of 1 to 1 1-2 to 2 1-2 and the like, we must double 
both numbers by which the ratio will not be altered, and consider them 
as compounds of 2 to 3, <fcc., as above. 

240. We must not omit to state that the atomic hypothesis has been, 
and to a certain extent is still disputed. Many years ago, it was thought 
to be settled that matter is infinitely divisible , and the question remained 
at rest till revived by Mr. Dalton. The preponderance of proof seems, 
now, on the side of the atomic theory ; and the laws of combination 
alone appear sufficient to establish it.* 

The Volumic Theory. 

241. A curious law was discovered in 1808, by Gay Lussac, which 
governs the proportions by measure , in which aeriform bodies combine. 
It appears from his experiments^ together with those of many other em¬ 
inent Chemists, that when two gases or vapors, combine, it is in the ratio 
by volume of 1 to 1,1 to 2, or some other simple ratio. Thus 1 volume 
of oxygen unites with 2 of hydrogen to form water ; 1 volume of vapor 
of sulphur to 1 volume of hydrogen form sulphuretted hydrogen, 1 volume 
of nitrogen and 3 volumes of hydrogen , form ammoniacal gas ; 1 volume 
of muriatic acid gas and 1 volume of ammonia , constitute muriate of ammo¬ 
nia. 

242. Further, from various considerations, it is inferred that the same 
law holds with regard to solid bodies which we cannot convert into Va¬ 
pors by the direct action of heat; so that when such bodies enter into 
gaseous combinations, their vapors are in a simple ratio wjth those of the 
other constituents. Thus we have good evidence, that carbonic acid is 
composed of 1 measure of the vapor of carbon to 1 of oxygen gas. 

243. Gaseous bodies sometimes undergo a condensation^ in combining, 
and sometimes not; but whenever a diminution of volume takes place, 
it likewise bears some definite and simple relation to the original bulk of 
the constituents, being one half, one third, &c. For example, no con- 

* Dr. Wollaston advocated the Atomic Theory in a very able disserta¬ 
tion upon the “Finite extent of the atmosphere” published in Eng¬ 
land in the Philosophical Transactions for 1822; and Professor Mitsch- 
erlich has treated of the same subject in his lucid observations upon the 
connections between the form and composition of bodies.” 


239. A third supposition by which the exceptions to the law of mul¬ 
tiples may be accounted for. 

240. The atomic theory not undisputed. 

241. Law of volumes discovered by Gay Lussac. Explanation of this 
law. 

242. Solids supposed to be subject to this law. Examples. 

243. Condensation of gaseous bodies explained in reference to the 

volumic theory. , 





VOLUMIC THEORY. 


101 


densation takes place in the formation of muriatic acid gas, but one vol¬ 
ume of chlorine and one of hydrogen form two volumes of the acid gas, 
on the other hand two measures of ammoniacal gas consist of one meas¬ 
ure of nitrogen and three of hydrogen ; so that here the two simple gas¬ 
es in uniting, are condensed to one half. Again two measures of nitro¬ 
gen and one of oxygen, form one of protoxide of nitrogen ) the conden¬ 
sation is, therefore, one third. 

214. Another curious result seems to flow from these facts. We con¬ 
sider that water as a compound of one atom of each of its constituents ; 
yet we know by experiment that it contains two measures of hydrogen 
and one of oxygen. The protc xide of nitrogen, also consists of two 
volumes of nitrogen and one of oxygen ; it contains, nevertheless, one 
atom of each. It therefore follows, that the atom of oxygen is but half 
as large as the atoms of nitrogen and hydrogen. There are several other 
bodies, whose combining proportions, like that of oxygen is represented 
by half a volume; but for the greater part of substances, a volume and 
an equivalent are synonymous. 

245. It is evident that the laws of combination by weight, and those 
which govern the proportion by volume must depend on the same cir¬ 
cumstances, the atomic constitution of matter. There is, however, one 
striking distinction between them. The proportions by weight in which 
two bodies unite, have no very remarkable dependence on each other. 
For example, 6 parts or atoms of carbon and 8 of oxygen form carbonic 
oxide ; now 6 is not to 8 in any simple ratio. The proportions by weight 
exist between the different quantities of the same body that combine 
successively with a given quantity of another body. But by the law of 
volumes, not only have we the dependence just referred to, but there is 
an evident relation between the bulks of the two substances. 


LECTURE IX. 

CHEMICAL CLASSIFICATION —DIVISION OF PONDERABLES.—OXYGEN. 

246 . By chemical analysis we reduce ponderable bodies to 
their ultimate elements, which we call simple substances , or ele¬ 
ments. 

Elementary bodies consist of two divisions: 

1st. Non-Metallic. 

2d. Metallic. 

244. The volume of an atom of oxygen compared to the atoms of hy¬ 
drogen and nitrogen. 

245. On what must combinations by weight, and by volume depend ? 
Distinctions between the two cases. 

246. Division of elementary bodies. Division of non-metallic bodies. 
Number of electro negative substances. Of electropositive substances not 
metallic? Number of metals. What is the electrical character of the 
metals ? 





102 


INORGANIC CHEMISTRY. 


The Non Metallic elements are divided in two classes , according 
to their electrical affinities ; those which are attracted to the pos¬ 
itive pole, possess the opposite or negative electricity, and are 
called electro-negative. Those which are attracted to the nega¬ 
tive pole , possess the opposite or positive electricity, and are cal¬ 
led electro-positive. 

1st. Class. 2d. Class. 


Electro-negative. 
Oxygen 
Chlorine 
Bromine 
Iodine 
Fluorine 


Electro-positive. 
Hydrogen 
Nitrogen 
Carbon 
Boron 
Silicon 
Phosphorus 
Sulphur 
Selenium. 

8 Electro-positive ele- 
ments. 

Besides these, there are 41 elementary substances which are 
metals , though some of them exhibit properties widely differing 
from gold, silver, and other common metals. The metals are all 
electro-positive. 

Electro-negative Substances. r 


5 Electro-negative 
elements. 


247. The Electro-negative Substances combine with the simple 
electro-positive bodies ; the latter are called combustibles , and the 
former, supporters of combustion. 

The electro-negative substances unite, also, with each other ; 
and in this case, one of them is positive, and the other negative. 
Such combinations, however, are extremely feeble, and their ele¬ 
ments are, consequently, easily disunited. But while they are 
weak in regard to the affinity which holds them together ; the 
facility of their decomposition causes them to act with great en¬ 
ergy upon other bodies. 

At the head of this class of simple elements is, 

OXYGEN.* 

248. The simplest form under which we are acquainted with 
oxygen is, that of a gas : in which state, like all other gases, it 

* From the Greek oxus , acid, and gcnnao , to generate. The German 
Chemists call it sauerstoff, which, literally, signifies sour stuff. 

247. General description of electro-negative substances. Their union 
with each other. 

248. State in which we are acquainted with oxygen. Its discovery. 
Synonymes. The name founded in error. 





OXYGEN. 


103 


is conceived to be a compound of a solid, ponderable basis, with 
caloric, and, perhaps, with light and electricity. 

Oxygen was discovered by Dr. Priestly in 1774 ; a discovery 
which was the cause of very important changes in the state of 
chemical science. It has been called Bephlogisticated air , Em¬ 
pyreal air , and Vital air. Lavoisier gave it the name of Oxy¬ 
gen, supposing it to be the sole cause of acidity, and it retains 
the appellation, though it is now known that there are other acid¬ 
ifying principles, as some acids contain no oxygen , and many of 
the oxides have no acid properties. 


Mode of obtaining Oxygen Gas . 


249. Most of the oxides are decomposed by red heat; and if the opera- 
tipn be performed in proper vessels, the expelled oxygen gas may be 
collected. Red Lead, which is the deutoxidc of lead, yields oxygen when 
heated to redness in an iron retort; by this loss of oxygen it is reduced 
to a protoxide. Red oxide of mercury, treated_ in the same way, is re¬ 
solved into oxygen and metallic mercury ; nitrate of potassa , (nitre or 
salt-petre,) kept at a dull red heat in an iron or earthen retort, yields 
oxygen gas in considerable quantities. The residue is hypo-nitrite of 
Potassa. This mode is dangerous without a cautious regulation of the 
heat. 


Fig. 39. 


A, represents a furnace 
in which is placed the re¬ 
tort B, containing the 
substance which is to fur¬ 
nish the gas. C, is the 
pneumatic cistern or wa¬ 
ter tube, D, the bell-glas3 
receiver, E F, a shelf in 
the cistern on which the 
receiver being filled with 
water and inverted, is 
placed. The water in the 
cistern rises a few inches 
above the shelf, so that 
the water in the receiver 
is supported by atmos¬ 
pheric pressure. The gas issuing from the retort passes through a bent 
tube, and is conducted by it under the shelf, into the mouth of the re¬ 
ceiver, and being lighter than water, it rises in bubbles and displaces 
the water in the upper part. This process continues until all the water 
in the receiver has gradually disappeared, and the vessel is filled with 



oxygen gas. 

250. The black oxide of maganese , when pulverized and heated in a 
retort, also furnishes oxygen gas. From the state of peroxide , it is thus 
reduced to that of deutoxidc, losing about 128 cubic inches of oxygen for 
each ounce of the material. As this mineral often contains carbonate of 
lime which would introduce carbonic acid into the oxygen, it ought to 


249. Substances from which oxygen may be obtained. Experiment 
representing oxygen. 

250. Oxygen obtained from the black oxide of manganese. 





















104 


INORGANIC CHEMISTRY. 


be previously purified by digesting it with very dilute muriate or nitric 
acid. The same oxide yields twice as much oxygen, if after being puri¬ 
fied, it is made into a paste with sulphuric acid and heated in an earthen 
retort. In this case it is converted into protoxide of maganese, losing a 
whole equivalent of oxygen, instead of half a proportional as in the for¬ 
mer case. The residue is Sulphate of Protoxide of Maganese : the sul¬ 
phuric acid combining readily with this oxide of maganese, though it 
cannot with the deutoxide or peroxide. 

251. A process, eligible in small operations, but too expensive for 
large ones, is to heat chlorate of potassa in a green glass retort.* A 
spirit lamp is the best source of heat for this experiment. The salt may 
be made to yield, for each 124 grains, 48 grains or141 cubic inches of 
oxygen gas; and there will remain in the retort 76 grains of chloride of 
potassium. The gaS thus obtained is absolutely pure. In all these pro¬ 
cesses the gas may be collected over water. 

252. Oxygen gas is transparent and colorless ; it is the least 
powerful refractor of light among the gases, and has the spe¬ 
cific gravity of 1.1111, air being 1, or 16 if hydrogen be taken as 
the standard. Its combining proportion is 8. It is said to emit 
light as well as heat, when suddenly and strongly compressed. 
It is tasteless and inodorous ; it is a non-conductor of elec¬ 
tricity, and is only very sparingly absorbed by water. It 
is the most perfect negative electric; suffers no chemical 
change by the action of the imponderables, wherefore it is 
considered a simple body; and has extensive and energetic 
chemical affinites, combining with every simple body without 
exception. 

253. The act of combining with oxygen, is called oxidation , 
and the body which has Combined with it, is said to be oxidiz¬ 
ed. It has neither acid nor alkaline properties, but some of its 
compounds are acids, some are salifiable bases, and some are 
neither acids nor bases. It frequently combines in several pro¬ 
portions, with the same body, producing entirely distinct com¬ 
pounds ; and may even form with the same metal an acid, and 
a salifiable base—when this occurs,, the acid is the compound con¬ 
taining the greatest proportional quantity of oxygen. 

Combustion. 

254. Oxidation may take place in two modes ; either slowly , 
in which case the progress of the chemical change is not percep- 

* Green glass is preferable, because without great care, the more fusi¬ 
ble white glass would be melted. 


251. Oxygen from chlorate of potassa. 

252. Properties of oxygen. Its relation to electricity. 

253. Oxidation. Nature of its compounds. 

254. Two modes in which oxidation may take place. Rusting of 
metals. Combustion of wood, candles, &c. 




OXYGEN. 


105 


tible ; or rapidly , in which case, heat and light are emitted, and 
the phenomena of combustion exhibited. Of the former, the 
gradual rusting of metals in the air, is an example; while the 
combustion of wood, candles, &c., is an instance of the latter. 
It sometimes happens that a higher oxide of a particular body, is 
produced by rapid, rather than by slow oxidation ; and often, on 
the other hand, the same compound is formed by either mode. 
Thus the brilliant sparks that fly from iron on a smith’s forge, 
and those struck from steel by a flint, are iron burning in the ox¬ 
ygen of the air ; and when cold, are found converted into the 
same oxide which is the basis of iron rust. 

255. The oxygen of the air, is the sole cause of its supporting 
combustion; and, since this gas constitutes only one fifth of the 
whole bulk of the atmosphere, it might be supposed that bodies 
which burn in air, would burn much more vividly in oxygen gas; 
this is found to be the fact. 


Fig. 40. 



Experiment 1st. u Let there be two bell glasses, A and B , 
communicating with each other by a flexible leaden pipe, with 
a stop cock at C. Suppose A to be placed over a lighted can- 

255. Why the air is a supporter of combustion. Ex. 1st. to show 
that a candle will be instantly extinguished in a vacuum, and burn but 
a short time in a small portion of atmospheric air. The experiment va¬ 
ried, to show the effect of introducing an atmosphere of oxygen gas into 
a bell glass containing a candle nearly extinguished for want of atmos¬ 
pheric air. 


10 




























106 


INORGANIC CHEMISTRY. 


die on the plate 7), which communicates with an air-pump, plate 
as represented at E. It will be found that the candle w T ill grad¬ 
ually burn dimly, and will at last go out, if no fresh supply be 
allowed to enter the bell glass ; if, on repeating the experiment, 
the air be withdrawn by means of the pump, the candle will be 
rapidly extinguished. It is therefore proved, that a candle will 
not burn in a vacuum, and that it can burn but for a short time 
in a small portion of atmospheric air. 

Let the experiment be repeated with the following change. 
Let the air be exhausted from both vessels, the stop cock C, re¬ 
maining open, until the bell 7?, is filled with water from the pneu¬ 
matic cistern. The stop cock being closed, fill the bell glass with 
oxygen gas. Now introduce a candle under the bell A, then hav¬ 
ing placed the bell again on the plate of the air-pump, exhaust 
the air, until the candle is nearly extinguished, and then open 
the stop cock so as to allow the oxygen from B, to enter. The 
candle will burn much more brilliantly, and for a longer time, 
than in the same portion of atmospheric air.” # 

Experiment 2nd. A slip of pine wood of the size of a match, 
ignited at one end, but not flaming, will be kindled instantly into 
flame, on being immersed in oxygen gas. 

Experiment 3d. A coil of 
Fig. 41. fine iron wire, burns in oxygen 

with beautiful scintillations. The 
wire must be tipped with sulphur, 
or some other combustible mat¬ 
ter and ignited to commence the 
combustion. The globules of 
melted and burnt iron, if they 
fly against the bell glass, always 
break it; and they have even 
been known to perforate, and 
pass through it. 

Experiment 4th. Phosphorus 
burns in oxygen, with a light so 
dazzling, the that the eye can 
scarcely contemplate it. 

255. After substances have 
burned for a time in oxygen gas, 
the combustion ceases ; in many 
cases the gas disappears, and if 
the operation be performed in a 

* Dr. Hare. 



Experiment 2nd. Experiment 3d. Experiment 4th. 






OXYGEN. 


107 


bell glass over water, the latter fluid will be seen to rise in the 
vessel, to supply the place of the consumed oxygen. This is 
the case when iron or phosphorus is used; for the oxygen 
unites with the latter, producing dense white fumes of phos¬ 
phoric acid , which condenses upon the side of the vessel as the 
acid cools, or dissolves in the water ; for phosphoric acid, though 
it first appear as a vapor, is naturally a solid, soluble in water. 
When iron burns in oxygen, the black oxide oj iron is formed, 
and takes at once the solid state. 

In some cases there is no apparent diminution of oxygen gas, 
because the new compound is gaseous ; thus sulphuric acid, and 
carbonic acid, produced respectively by burning sulphur and char¬ 
coal in oxygen, are gases, of the same bulk, as the oxygen em¬ 
ployed in forming them. But oxygen gas has nevertheless been 
consumed ; for on examining the residual gas, it will be found to 
exhibit an entirely new set of properties,being in fact a new body, 
a compound of the combustibles with oxygen. Accordingly, no 
combustible will burn in it. 

256. Oxygen was formerly supposed to be the only supporter 
of combustion ; but more recently, many other bodies are found 
to evolve light and heat, in combining with each other. This is 
particularly the case during the combustion of electro-positive 
with electro-negative bodies ; and the term, supporters of combus¬ 
tion has been applied to all the latter, as distinguishing them from 
the former, which are called combustibles. But light and heat 
are often emitted by two electro-positive bodies, while combin¬ 
ing with each other, as in the case of iron and sulphur, and cop¬ 
per and sulphur ; so that the term supporters of combustion , can 
scarcely be regarded as proper, though, in accordance with cus¬ 
tom, we may use it. The term combustion , also, is now used in 
a more enlarged sense than formerly, including not only, rapid 
oxidation, but all other cases of chemical combination in which heat 
and light are eliminated. 

257. One of the first who attempted to explain the cause of 
combustion, was Stahl, a German. He supposed that a certain 
substance, which he called phlogiston , (from the Greek phlogizo , 
to burn,) formed a part of all combustible bodies, and that, in 

255. Why water will rise in the bell glass after oxygen has been con¬ 
sumed. Production of phosphoric acid. Formation of the oxide of iron. 
Why in some cases, there is no apparent diminution of oxygen gas. 
Production of sulphuric acid—of carbonic acid. 

256. Oxygen not the only supporter of combustion. Terms support¬ 
ers of combustion and combustibles, to what classes of bodies applied ? 
Light and heat sometimes emitted by electro-positive bodies. The term 
combustion, how used at present ? 

257. Stahl’s theory of combustion. Lavoisier’s theory. 



108 


INORGANIC CHEMISTRY. 


every case of combustion, this inflammable principle was disen¬ 
gaged. Now, as a metallic wire, after burning in oxygen gas, is 
heavier than before combustion, it follows, that instead of hav¬ 
ing parted with something in the process of combustion, it has 
actually gained in weight. Therefore, instead of giving out 
this imaginary phlogiston, it is found to have united with ox- 
ygen. 

Lavoisier finding that the new discovery of oxygen gas de¬ 
stroyed the phlogistic doctrine, was led to investigate the sub¬ 
ject of combustion, and after years of patient research, he published 
the theory that oxygen is the only supporter of combustion. On 
this supposition, he conceived that in all cases of combustion, 
the solid base of oxygen gas united with the combustible body ; 
and that the light and heat of the oxygen gas, being thus set free, 
give rise to the phenomena of combustion ; from this theory it 
would follow, 1st, that the specific caloric of the new compound, 
is always less than the mean of those of the constituents. And, 
2d, that all combustibles, in consuming the same quantity of ox¬ 
ygen gas, must give out the same quantity of light and heat. 
Now both of these conclusions are contrary to experience ; be¬ 
sides which, as before stated, the fundamental proposition, that 
oxygen is the only supporter of combustion, is likewise untrue. 
So that the theory of Lavoisier, is liable to serious objections. 
But, as Dr. Turner justly remarks, u It is easier to perceive the 
fallacy of one doctrine, than to substitute another that shall be 
faultless.” 

258. Substances which have been burned in oxygen, are no 
longer capable of combustion ; they are new bodies, having an 
entirely new set of properties. They have gained weight; and, 
ey making the experiment with the requisite care, it will be 
found that their increase is precisely equal to the oxygen con¬ 
sumed. Some bodies, on being heated after combustion, yield 
precisely the same quantity of oxygen which disappeared during 
the experiment, and thus return to their original condition. 

Respiration. 

259. Ox}^gen is the only gas which supports respiration, and 
it is owing to the presence of this gas, that animals can live in 
common air. Physiologists agree that its effect in supporting 
life, depends on its action upon the blood. If a portion of this 


258. Change in substances which have been burnt in oxygen. 

259. Agency of oxygen gas in respiration. Experiment showing the 
effect of oxygen upon the blood. How does oxygen affect the blood in 

espiration ? Arterial and venous blood. 



OXYGEN. 


109 


fluid be drawn from a vein , it is perceived to have a dark color, 
approaching to black; put it into a bell glass filled with oxygen 
gas, and it will very soon become florid red; and the same 
change will ensue, though not quite so rapidly, if the blood be 
exposed to common air. The air in the jar being examined, is 
found to have lost ox}^gen, and to have acquired an equal bulk 
of carbonic acid. This is precisely what takes place in respira¬ 
tion. The blood as it issues from the left cavity of the heart 
into the arteries , and is distributed by them through the system, 
is called arterial blood , and has the florid color of that above 
mentioned. Having completed its circulation, it returns through 
the veins ; and here it is found to have acquired a larger quantity 
of carbon, and become dark colored ; in this state it is called 
venous blood. 

260. Before it goes again into circulation, it passes through 
the spongy organ, called the lungs ; throughout which it is dis¬ 
tributed in the countless microscopic tubes into which the veins 
have branched out, so as to expose the greatest possible surface, 
Here it comes in contact with the air with which the lungs 
have been inflated by the last inhalation ; the excess of carbon in 
the blood combines with oxygen, and forms carbonic acid gas, 
which is exhaled with the nitrogen of the air; the blood thus 
purified and rendered fit for circulation, passes on through the 
appropriate vessels to the left cavity of the heart, and is again 
distributed through the system. The air which is exhaled, hav¬ 
ing exchanged oxygen for carbonic acid, is no longer fit for sup¬ 
porting combustion and respiration ; and this is one of the rea¬ 
sons why crowded and strongly illuminated rooms, are unhealthy. 

But although oxygen gas is the sole supporter of respiration, 
it is too stimulating in its effects on the human system to be in¬ 
haled in an unmixed state. If inhaled in any considerable quan¬ 
tity, it produces fatal inflammation of the lungs. It is possible 
that warm climates may be beneficial to consumptive persons, 
because the air being warmer, is less dense than in cold climates, 
and each inspiration, therefore, brings a smaller quantity of oxy¬ 
gen into contact with the lungs, which in a debilitated state are 
unable to bear the more oxygenated and consequently more stim¬ 
ulating air of a colder climate. 

260. Change which takes place in the blood, in passing through the 
lungs. One cause of the unhealthy effect of breathing the air of crowd¬ 
ed rooms. Effect of breathing pure oxygen. Why persons with weak 
lungs require a warm climate. 

10 * 



110 


INORGANIC CHEMISTRY. 


LECTURE X. 

ELECTRO-NEGATIVE SUBSTANCES.-CHLORINE. 

261. Chlorine gas was formerly known under the names of 
Oxygenized Muriatic acid , and Oxymuriatic acid ; which names 
arose from the belief then entertained, that it is a compound of 
muriatic acid and oxygen. It was discovered by Scheele in 
1774, who called it Dephlogisticated marine acid. 

262. Chlorine gas may be obtained 
by mixing strong muriatic acid and per¬ 
oxide of manganese in a flask or retort, 
and heating the mixture gently with a 
lamp. An effervescence arises, owing to 
the escape of the gas w hich may be col¬ 
lected in a bell glass over warm w r ater; 
but a better way is to make it pass through 
a tube bent twice at right angles, the dis¬ 
engaged leg of which passes into a glass 
bottle, descending nearly to the bottom. 
The gas, by its superior gravity, displaces 
the atmospheric air as water w r ould, and 
fills the bottle, which is known to be full 
w r hen the green color of the gas pervades 
it; it should then be carefully closed by a 
well ground glass stopper. Great care should be taken not to 
inhale the gas, nor to permit its escape into the room in any con¬ 
siderable quantities, as its effects on the lungs are highly dele¬ 
terious. In this process a portion of the muriatic acid is decom¬ 
posed ; its hydrogen combines with one atom of the oxygen of 
the manganese, and forms water, while the chlorine is disengag¬ 
ed. The peroxide of manganese by losing one atom of oxygen, 
becomes the protoxide , the latter remains in the retort w r ith a 
portion of undecomposed muriatic acid forming a Muriate of the 
protoxide of manganese . 

Another process for obtaining Chlorine is used when very large quan¬ 
tities are required. It consists in heating in a retort, A, three parts of 
common salt (chloride of sodium) and one of peroxide of manganese, 
thoroughly mixed, and two parts of sulphuric acid, diluted with its own 

261. Various synonymesof chlorine. 

262. Mode of obtaining chlorine with muriatic acid and peroxide of 
manganese. Rationale of this process. Mode of obtaining chlorine with 
common salt and peroxide of manganese. Explanation. 















CHLORINE. 


Ill 


Fig. 43. 



weight of water. The lamp 
being placed under the retort, 
the mixture heats gradually, and 
the chlorine gas being driven off, 
passes through the back of the 
retort under the inverted bell 
glass C, which is at first filled 
with water ; as the gas rises, the 
water subsides, until the whole 
receiver is filled with chlorine. 

The chemical changes in this 
experiment are as follows; The 
sulphuric acid acting upon the solution of chloride of sodium, or com¬ 
mon salt, disengages muriatic acid ; the latter is decomposed by the 
peroxide of manganese, as explained in the former experiment; the 
sulphates of soda and manganese remain in the retort. 

263. Chlorine gas is of a green color, slightly yellowish, and 
derives its name from the Greek word which signifies green. 
It has an astringent taste, and a disagreeable, suffocating odor. It 
is exceedingly deleterious when inhaled, even though diluted 
with air. It is said to give out light , when suddenly compress¬ 
ed with great force ; a property belonging to no other gases but 
oxygen and chlorine. When the hand is immersed in chlorine 
gas, a distinct sensation of warmth is perceived, though the real 
temperature is the same as that of the room. Its combining 
number is 36, and its specific gravity 2.5. A pressure of 4 
atmospheres, (about 60 lbs to the square inch,) reduces it to a 
bright yellow liquid, which does not congeal at zero, and which 
resumes the gaseous form instantly, when the pressure is removed. 

Cold water dissolves about twice its bulk of chlorine, forming 
a solution which has the color, odor and general properties of the 
gas itself; and hence the necessity of heating the water over 
which chlorine gas is to be collected. If exposed to a tempera¬ 
ture of 32° Fahrenheit, while mixed with watery vapor, it forms 
a solid hydrate,* which appears in the form of crystals, on the 
sides of the bottle ; this hydrate is liquefied by the warmth of 
the hand. 

264. Neither heat, light, electricity, nor galvanism has been 
able to decompose pure chlorine. It is therefore considered as a 
simple element. When chlorine is in a moist state, the watery 
vapor may be decomposed, the chlorine combines with the hy- 


* A hydrate is a compound of water with another body, often in definite 
proportions. 


263. Properties of chlorine. 

2G4 Effects of cold on chlorine gas. Why considered a simple ele¬ 
ment. Chlorine decomposes watery vapor in contact with it. Is an in¬ 
direct oxidizing agent. 














112 


INORGANIC CHEMISTRY. 


drogen of the vapor, and the oxygen which formed part of the 
same is liberated. This takes place in the sunshine, slowly in 
the shade ; the moist gas, or its solution, cannot be preserved 
long, except in the dark ; the bottle containing either, should 
therefore be coated with black paper. As oxygen must be liber¬ 
ated whenever chlorine decomposes water, if an oxidable body 
be at the same time present, it will become oxidized ; so that 
chlorine is often an indirect oxidizing agent, of great power. 

265. Chlorine supports the combustion of some bodies. If a 
lighted candle be immersed in it, it goes out after burning a 
short time with a dull red flame. Phosphorus, and some of 
the metals, (the latter being in powder or thin leaves,) take fire 
spontaneously in this gas. Some of the metals which exhibit 
this property, are potassium, zinc, tin, copper, powdered anti¬ 
mony and arsenic. In all these cases, combination takes place 
between the burning body and chlorine, and. the compound re¬ 
sulting is a chloride. 


Fig. 44. 



Experiment. The bell glass B, represents the combustion of 
gold leaf in chlorine ga&. The lower bell glass A, being filled 
with chlorine over the pneumatic cistern; the upper bell glass is 

265. Chlorine is an impf-rfect supporter of combustion. Compound 
which results from the burning of a metal with chlorine. Experiment 
showing the combustion of gold leaf in chlorine gas. 














CHLORINE. 


113 


exhausted of air by means of an air pump, and the pipe which 
is connected with the apparatus. On turning the stop-cock be¬ 
tween the two bell glasses, the gas from the lower one rushes 
up to fill the vacuum, and the gold leaf is immediately inflamed, 
and burns with great brilliancy, forming chloride of gold. 

266. As chlorine unites with simple bodies it cannot be an 
acid ; for acids combine only with metallic oxides and not with 
the metals themselves. Besides, it has none of the other prop¬ 
erties of acids. 

It is the most intensely electro-negative body known except 
oxygen ; and is, consequently, always found at th e positive pole, 
when a compound of it with any other substance than oxygen is 
decomposed by a galvanic battery. Its affinity for metals is even 
greater than that of oxygen ; so that if a metallic oxide is heat¬ 
ed in chlorine gas, the oxygen is expelled, and a chloride of the 
metal is formed. 

267. Chlorine is a re-agent of the highest importance ; and 
some of its chemical properties render it extensively useful in 
the arts of life. It bleaches very powerfully, destroying the 
vegetable colors rapidly. This will not take place, however, 
unless moisture is present; and the bleaching is supposed to de¬ 
pend upon the decomposition of water. In this case, the bleach¬ 
ing effect must be due to the oxygen liberated from the decom¬ 
posed water, and chlorine only performs the part of an indirect 
oxidizing agent. There are other facts in support of the same 
opinion, one of which is, that certain highly oxidized bodies, as 
deutoxide of hydrogen, and manganese acid, are powerful bleach¬ 
ing agents. 

For bleaching on the small scale, as in removing from linen and cot¬ 
ton, the stains of fruit or other vegetable substances, the solution of the 
gas in water, maybe used. But this solution in large quantities, gives 
off so much gas as to be deleterious to the workmen ; and the resulting 
muriatic acid is injurious to the texture of cloth. Both these inconve¬ 
niences are avoided by using the chloride of lime y commonly known as 
bleaching powder. 

Experiment. Immerse a piece of litmus paper, or of printed calico, in 
a solution of chlorine, or of chloride of lime, or into a jar of the gas it¬ 
self ; (in the latter case, the calico or paper must be moistened ;) the col¬ 
or will be discharged in a short time. 

268. Chlorine derives much importance from the great facil- 


266. Proof that chlorine is not an acid. Its electrical affinity. Its 
affinity for metals. 

267. Various uses of chlorine. Its bleaching properties. The par¬ 
ticular office of chlorine in the bleaching process. Proofs that oxygen 
is the active agent. Reasons for preferring the chloride of lime in bleach¬ 
ing, to the gas in solution. Experiment to prove the bleaching power 
of chlorine. 

268. Effect of chlorine upon animal or vegetable poisons. 



114 


INORGANIC CHEMISTRY. 


ity with which it destroys animal and vegetable poisons, wheth¬ 
er existing as miasma in the atmosphere or in other forms. 

The air of a sick person’s chamber, is purified in a few minutes, by 
sprinkling the floor with a solution of chloride of lime or soda. The 
putrescence of meat is arrested, and the taint removed by the same sub¬ 
stances, which, likewise, in a dilute state, form an admirable wash for 
the mouth. Chlorine, in fhe gaseous state, and in solution in water, is a 
certain antidote for Prussic acid ; and it seems highly probable that the 
bite of a rattlesnake, or of a rabid animal would not be followed by such 
fearful consequences, if, as soon as they occur, the wounds could be 
dressed with the aqueous solution of this gas. 

It is not ascertained whether chlorine acts directly upon the 
poisonous matter, or whether it is in this case, as in its bleach¬ 
ing action, an indirect oxidizing agent. In either case, affinity 
for hydrogen* is probably the cause of the phenomena. 

269. When chlorine is passed into a cold solution of a fixed alkali, it 
is absorbed in considerable quantity, and forms a compound which exhib¬ 
its the odor,'the bleaching effects, and the antiseptic properties of chlo¬ 
rine. A disinfecting liquid, prepared by M. Labarraque, which is a form 
of chloride of soda, is such a compound. But if the compound be heat¬ 
ed, or if the alkaline solution be hot when gas is passed into it, the re¬ 
sult is quite different. Water is then decomposed ; five atoms of chlorine, 
take five of hydrogen, and form five of muriatic acid, which unite with 
five of the alkali, forming a muriate; the five atoms of oxygen disen¬ 
gaged from the water, combine with one of chlorine, and constitute a 
particle of chloric acid , which also combines with one of alkali, and 
forms a chlorate. The solution thus contains nothing but two neutral 
salts, a muriate and chlorate, and has no longer the distinguishing char¬ 
acters of chlorine. 

270. Chlorine is detected by its bleaching property, and by 
producing, in a solution of nitrate of silver , a white, curly pre¬ 
cipitate, which soon becomes dark colored, on exposure to light. 
This precipitate is the chloride of silver. 

Compounds of Chlorine and Oxygen. 

271. These two electro-negative substances cannot be made 

* Wherever we commence in our instructions in science, we must, oc¬ 
casionally, refer to what is yet unexplained. This is peculiarly the case 
in Chemistry. The three most important of the elementary bodies, are 
Oxygen, Hydrogen, and Nitrogen; they fofm combinations with all oth¬ 
er know r n elements. But in our system of arrangement, according to 
electro-chemical agencies, oxgen stands at the head of one division, and 
hydrogen at the head of another. We must therefore, in adhering to our 
arrangement, leave the consideration of hydrogen and nitrogen , till we 
have treated of the simple electro-negative bodies, though some of tho 
latter are of much less importance. 

269. Disinfecting liquid, how prepared? Effect of passing chlorine gas 
into a hot alkaline solution. 

270. Test of chlorine. 

271. Names and composition of the compounds of chlorine and oxygen. 
Their most striking character. These compounds not found native. 



CHLORINE. 


115 


to unite by the direct method ; but indirectly we are able to pro¬ 
duce four distinct compounds of them. Their names and com¬ 
position are as follows, 


Protoxide of chlorine 

Chlorine. Oxygen. 
36 add to 8 

Chlorine, 
or 1 atom 

Oxygen, 
add to 1 atom 

Peroxide of chlorine 

36 “ 

32 

or 1 “ 

u 4 (t 

Chloric acid 

36 “ 

40 

or 1 “ 

“ 5 “ 

Perchloric acid 

36 “ 

56 

or 1 “ 

U 7 u 


The most striking character of these compounds is the ex¬ 
treme facility with which they are decomposed, either by heat 
or by the action of other substances. This property is the ne¬ 
cessary result of the very weak affinity of chlorine and oxygen 
for each other, and the powerful attractions of each for other 
simple bodies. None of these compounds has ever been found 
as a natural production. 

272. Protoxide of chlorine* 1 ch. 36 add to 1 ox. 8=441 
Peroxide of chlorine 1 ch. 36 add to 4 ox. 32 68. 

The properties of these two substances may be advantageously studied 
by comparing them with each other. They are both gaseous, and both 
of a greenish yellow color; but the color of the peroxide is of a richer 
and deeper tint than that of the protoxide. They are both copiously ab¬ 
sorbed by water, to which they communicate their color, odor and some 
of their chemical properties They are both highly explosive and dan¬ 
gerous compounds : the protoxide explodes by even the heat of the hand, 
and the peroxide at about the boiling heat of water. Both these gases 
bleach powerfully, provided moisture be present; their solutions in 
water possess the same property ; but the protoxide reddens a vegetable 
blue before it bleaches it, while the peroxide whitens it, at once. 

273. Phosphorus takes fire spontaneously on being immersed in either 
of the gaseous oxides of chlorine; explosion immediately takes place, 
and the phosphorus continues to burn in the two component gases, form¬ 
ing a compound of each. 

Expansion is a necessary consequence of the decomposition of these 
gases ; for in each of them the two elementary gases are in a state of 
condensation. In the protoxide, 4 measures of chlorine and 2 of oxygen, 
making 6 measures, are so condensed by combination as to form but 5 
measures of the oxide. In the peroxide, the contraction is still greater, 

* The student will understand that 36, the combining proportion of 
chlorine, being added to 8 the combining number of oxygen, makes 44 
which is the chemical equivalent of the protoxide of chlorine. The pe¬ 
roxide haring four proportions of oxygen to one of chlorine, its chemi¬ 
cal equivalent is 68. 

t The protoxide of chlorine was named by Sir H. Davy, Enchlorine 
signifying very green. 

272. What are the component parts, and chemical equivalents of the 
protoxide and peroxide of chlorine ? Comparison of these two substances 
with each other. Their bleaching properties. 

273. Phosphorus and other bodies in a state of combustion, immersed 
in either of these gases. 




116 


INORGANIC CHEMISTRY. 


for 4 measures of this gas contain 6 of the component gases, of which 2 
are chlorine and 4 are oxygen. The peroxide, therefore, explodes more 
violently than the protoxide. 

274. Chloric acid is obtained in solution, by adding sulphuric 
acid to a solution of chlorate of baryta . The insoluble sulphate 
of baryta/ is precipitated, and pure chloric acid remains in solu¬ 
tion. It may be obtained in a solid state, by evaporation. It 
was formerly called hyperoxy-muriatic acid , its salts are still call¬ 
ed, by some hyper oxy-muriates. 

Chloric acid reddens litmus paper, tastes sour and combines 
with the alkaline bases, forming salts called chlorates. It does 
not, like chlorine bleach, nor precipitate solution of silver. It 
readily affords oxygen to oxidable bodies, acting on them with 
great violence. Its salts, the chlorates , have the same property, 
deflagrating with great violence on hot coals, and producing a 
violent explosion when mixed with phosphorus or sulphur and 
struck with a hammer or heated. These experiments should 
only be made with small quantities, and great caution should be 
used in mixing the materials. The explosion arises from the 
rapid oxidation of the combustible part of the mixture, at the 
expense of the chloric acid. 

275. Chloric acid is also decomposed by sulphuretted hydrogen , the hy¬ 
drogen forming water with the oxygen of the acid, while the sulphur 
and the chlorine are set free. Sulphurous acid also, takes the oxygen 
from chloric acid, and becomes sulphuric acid, while the chlorine is lib¬ 
erated. 

The action of muriatic acid on chloric acid or chlorate of potassa , va¬ 
ries with the proportions in which they are mixed. If we mix six equiv¬ 
alents of muriatic acid, with one of chlorate of potassa one equiva¬ 
lent of the former will combine with potassa and form the muriate , 
which has nothing further to do with the decomposition. The 
chloric acid, being thus set free, reacts with the remaining five equiva¬ 
lents of muriatic acid, as follows : the five proportions of oxygen con¬ 
tained in the former, with the five of hydrogen in the latter, form five 
of water, consequently six equivalents of chlorine, (one from the chlo¬ 
rine and five from the muriatic acid,) are set at liberty. But if we de¬ 
crease the quantity of muriatic acid, the hydrogen of it being now in¬ 
sufficient for combining with all the oxygen of the chloric acid, the lat¬ 
ter loses only enough oxygen to become protoxide of chlorine , which 
comes over as a gas, mixed with the chlorine of the decomposed muriat¬ 
ic acid. The mixed gases being passed through mercury, the chlorine 
combines with mercury and is retained, while the protoxide of chlorine 

274. Cause of the expansion of these gases. How is chloric acid ob¬ 
tained ? Synonyme. Properties. Names of its salts. Its effect on ox¬ 
idable bodies. Deflagrating properties of its salts when mixed with 
combustibles. Cause of the explosion of these bodies when struck with 
a hammer or heated. 

275. Action of sulphuretted hydrogen with chloric acid. Action of 
muriatic acid on chloric acid or chlorate of potassa.^ Action of the disen¬ 
gaged chloric acid. How is the protoxide of chlorine formed, and how 
obtained ? Action of sulphuric acid on the chlorate of potassa. 



CHLORINE. 


117 


is to be collected in an inverted glass vessel^ This is the common pro¬ 
cess for procuring the protoxide , and its description has been delayed 
till now, that it might be the better understood. The proportions of mu¬ 
riatic acid and chlorate of potassa are regulated with a view to the evo¬ 
lution of the least possible quantity of free chlorine. Two parts by 
weight of the chlorate, one of strong muriatic acid and one of water are 
those recommended. 

The action of sulphuric acid on the chlorate of potassa is also remark¬ 
able. Instead of combining with all the potassa to form a sulphate , thus 
liberating the chloric acid, it only unites with & portion of the alkali and 
forms bi-sulphate. The portion of chloric acid thus expelled, is decom¬ 
posed; part of its oxygen goes to the acid of the undecomposed chlorate 
and converts it into perchloric acid, which remains in combination with 
potassa; the decomposed chloric acid by this loss of oxygen, is convert¬ 
ed into peroxide of chlorine, which may be collected. The solid residue 
is a mixture of bi-sulphate and perchlorate of potassa. Sulphuric acid 
would act in the same way on chlorate of soda, or any other chlorate 
with the base of which it forms a readily soluble salt; but the chlorates 
containing bases that form insoluble’ salts with sulphuric acid, are totally 
decomposed by it, furnishing solution of chloric acid as has been stated 
in regard to chlorate of baryta, (§ 274.) 

276. Perchloric Acid. The solid residue of bi-sulphate and perchlorate 
of potassa remaining after acting on chlorate of potassa, with sulphuric 
acid, as just described, being digested in water, the very soluble bi-sul¬ 
phate is dissolved, while the less soluble perchlorate is left nearly un¬ 
touched. If this be distilled in a retort with sulphuric acid, a solution 
of perchloric acid, will be collected in the receiver. It is volatile, de¬ 
composable in heat at a higher temperature than that necessary to decom¬ 
pose chloric acid, and forms a class of salts, which, like the acid itself, 
deflagrate with combustibles. Its salts like the chlorates, are convertible 
by heat into oxygen and chlorides of metals. Indeed the chlorates are 
converted by heat into oxygen and perchlorates, and then the heat must 
be somewhat raised, before the remaining oxygen is given off. Perchlo¬ 
ric acid is important, as affording the best method of distinguishing and 
separating potassa from soda ; for if it be poured into a solution contain¬ 
ing these alkalies, or their salts, it precipitates the perchlorate of potassa, 
which is nearly insoluble, while the perchlorate of soda is extremely 
soluble and remains in solution. 

277. The constituents of the two oxacids of chlorine are as follows j 

Chloric acid. 1 ch. 36, add 5 ox. 40=76. 

Per-chloric acid. 1 ch. 36, add 7 ox. 56=92. 


276. How is per-chloric acid obtained ? Properties. Character of its 
salts. Use of this acid. 

277. What are the constituents of the two oxacids of chlorine ? 

11 



118 


INORGANIC CHEMISTRY. 


LECTURE. XL 

ELECTRO-NEGATIVE SUBSTANCES.-BROMINE, IODINE, FLUORINE. 

BROMINE. 

278. Bromine is named from a Greek word signifying, 
u a rank odor.” It was discovered by M. Ballard, (of Mont¬ 
pelier, in France, about the beginning of 1826,) in sea-wa¬ 
ter, which is still the only source from which it is commonly 
obtained. Even there, however, it exists only in very minute 
quantity. It has been found in the water of some mineral springs. 
In all cases, it is found in nature in combination with hydrogen, 
forming hydro-bromic acid which is united with either potassa or 
soda. 

279. In its affinity for hydrogen, it ranks next below chlo¬ 
rine ; the latter body, therefore, affords the means of procuring it 
in a separate state. In order to obtain it, sea-water is evaporated 
till all but the most deliquescent and least crystallizable salts are 
deposited ; the residual liquid, called bittern ,* is then drawn off. 
Into this, chlorine gas is passed. The chlorine combines with 
the hydrogen and forms muriatic acid , and thus the bromine of the 
hydro-bromic acid is set free. 

280. Bromine is very soluble in sulphuric ether; therefore, in pouring 
some of this liquid into the decomposed bittern, an ethereal solution of 
bromine is formed, which being lighter than water, will float in a distinct 
stratum on the top, and can be poured off. The next step is to add po¬ 
tassa to the ethereal solution; bromide of potassium is formed, from which 
bromine is obtained by the addition of sulphuric acid and peroxide of 
manganese, for the same reason that chlorine is obtained by the same 
process, from chloride of sodium, (see §263 ;) but bromine being a liquid, 
instead of a bell glass, (as in the case of chlorine,) we must attach a cold 
receiver to the neck of the retort. 

281. This liquid is three times as heavy as water, of extreme 
volubility, giving off dense red vapors when in an open vessel, 

* Bittern is an uncrystallizable residue, after having extracted the 
common salt from sea-water. It contains several deliquescent salts 
among which is the hydriodate of sdda. 

278. Derivation of the name bromine—its discovery, and with what 
substances found. 

279. Mode of obtaining it through the agency of chlorine. 

280. Second mode of obtaining bromine. 

281. Properties of bromine. Its power of supporting combustion. 
Formation of bromides. Analogies of bromine with chlorine. How 
detected 




IODINE. 


119 


and is congealed into a brittle solid at about 4° below zero. In 
mass it is of a blackish red color, like venous blood ; but in a 
thin stratum, especially when held to the light, it is of a bright 
hyacinth red. Its vapor is acrid and penetrating, and its effect 
on the nostrils remains for some hours. It is noxious when 
inhaled, and very poisonous when swallowed. 

It is considered a simple body, not being decomposed by light, 
heat, or electricity. Its equivalent number is 75. It dissolves 
sparingly in water, mote freely in alcohol, and still more so in 
ether. Its vapor extinguishes a candle, but supports the com¬ 
bustion of several bodies. Phosphorus, potassium and a few 
other substances, take fire spontaneously and explode in contact 
with liquid bromine. In all cases of combustion in bromine, a 
bromide of the burning body is found. Bromine possesses 
bleaching properties, acts powerfully on animal and vegetable 
bodies and corrodes the skin. It resembles chlorine in its affini¬ 
ties, and other properties. 

282. Bromic Acid is the only known compound of bromine 
and oxygen, and has many of the properties of chloric acid. It 
consists of 1 equivalent of bromine and 5 of oxygen; is 
decomposed by heat, and forms a class of salts, called bromates , 
which deflagrate with the more oxidable bodies. This acid is 
obtained by acting on brornate of baryta, by sulphuric acid. 

283. Bromine and Chlorine. These two bodies unite, (probably in the 
proportion of one atom of each,) to form the Chloride of bromine, a dense 
liquid, of a reddish yellow color, and very volatile, giving off acid and 
strongly odorous vapors. It dissolves freely in water, without decompo¬ 
sition ; the bleaching properties of the two constituents, still remaining 
in solution. Its vapors set some substances on fire, producing at once a 
chloride and a bromide of the combustible. 

IODINE. 

284. Iodine is a solid substance, of a bluish black color, 
resembling in its appearance, the cuttings of a lead pencil. Its 
combining number, or atom is stated at 124. It is capa¬ 
ble of crystallizing, but is usually seen in the form of scales of a 
crystalline texture. It is about four times as heavy as water. 
It melts at 225°, and vaporizes at 347°; but it evaporates grad¬ 
ually, at ordinary temperatures, especially in a moist atmos¬ 
phere. 

Experiment. Put into a phial a small piece of iodine, and 

282. Composition of bromic acid. Analogies with chloric acid. Bro¬ 
mates. 

283. Chloride of bromine. Its properties. 

284. Properties of iodine. Experiment showing that iodine readily 
becomes a vapor. Properties of the vapor of iodine. 



120 


INORGANIC CHEMISTRY. 


hold it near the flame of a lamp. The solid will soon disappear, 
and the phial be filled with a vapor of a beautiful violet color, 
and hence its name iodine*. As soon as the phial is removed from 
the lamp, the iodine is again seen in the solid form, and without 
any apparent change in its nature. The vapor of iodine is ex¬ 
ceedingly heavy, having more than eight times the weight of 
air. If the vaporization be performed in a long tube or matrass, 
the vapor on reaching the cool part of the vessel, is condensed 
into minute, shining crystals. 

285. Iodine is considered a simple body, because, like chlo¬ 
rine and bromine, it cannot be decomposed. It requires 7000 
times its weight of water to dissolve it, and then gives a light 
brownish, yellow solution. In alcohol and ether, it dissolves 
much more copiously, forming a deep brown solution. Al¬ 
though iodine, alone has a much higher vaporizing point than 
water, yet on account of the affinity of these two bodies, the 
aqueous solution of iodine, is distilled without separating them. 
Iodine acts powerfully on the animal system, as an irritant 
poison ; but in some diseases, it is employed both externally and 
internally, in small doses, with great advantage. 

286. Iodine possesses strong affinities for the simple bodies, 
and weak ones, for oxides and other compound bodies. In gen¬ 
eral, whatever combines with chlorine or bromine, will unite 
also with iodine, forming analogous compounds. Its combina¬ 
tions with simple bodies are Iodides. Some substances, when 
brought into contact with iodine, take fire, especially in open 
air ; of these are phosphorus and potassium. Iodine destroys 
vegetable colors, but less powerfully than chlorine. Instead 
of bleaching them, it usually changes them to yellow. It 
leaves a yellow stain on the skin, which like that left by bro¬ 
mine, gradually disappears, on account of the volatility of this 
substance. 

287. To detect free iodine, the color of its vapor and its 
odor, which is like that of muriatic acid, but less strong, are 
sufficient; if in combination, the iodine must be set free by 
chlorine, or by oxide of manganese and sulphuric acid. But 
when in very minute proportion, iodine requires a more delicate 
test. A drop of the alcoholic solution of iodine added to a cold 

* From the Greek iodus , violet colored. 

285. Why is Iodine regarded as a simple body ? Its solubility. Effect 
on the animal system. 

286Affinities of iodine. Iodides. Effect of iodine on vegetable colors 
and on the skin. 

287. Tests of iodine. 



IODINE. 


121 


solution of starch will cause a beautiful blue iodide of starch to 
appear. Another mode of testing the presence of this substance , 
is to dissolve a little starch in a solution of pure potassa and add 
this solution to the liquid supposed to contain iodine, and after¬ 
wards drop in a little sulphuric acid, if a blue compound appears, 
it is caused by iodine. 

288. Iodine exists in sea-water, by which it is also imparted 
to sea-plants and animals. It is also found in the water of some 
mineral springs. It bears, however, a very small proportion to 
the other bodies with which it is mixed. Like chlorine and 
bromine, it is always in combination with hydrogen, constituting 
a hydracid, which is combined with a salifiable base. Sea water 
is believed to contain hydriodate of soda, or potassa, from which 

239. Iodine may be obtained by adding 
sulphuric acid to bittern , and applying 
heat. A portion of the sulphuric acid 
takes the soda of the hydriodate of soda 1 
and liberates the hydriodic acid. This re¬ 
acts on the remaining sulphuric acid, the 
oxygen of the latter uniting with the hy¬ 
drogen of the former to constitute water. 
The iodine of the hydriodic acid is thus 
disengaged, and the bittern becomes dark 
colored, on account of the free iodine. 
Let this liquid mass be now introduced 
into the retort a, through the tubulure b ; 
on placing the retort over the flame of a 
lamp, the violet colored vapors of iodine 
fill the retort, and rising into the receiver 
c, are condensed. If the receiver be cov¬ 
ered with a wet cloth, (as represented in 
the figure) it will assist in keeping it cool. 
The crystals of iodine are washed out of 
the receiver with a small quantity of wa¬ 
ter, and dried upon blotting paper which 
serves as a filter, the liquid passing through 
its pores, and the solid particles remaining on its surface. 

290. Iodic Acid. 1 Iod. 124, added to 5 ox. 40=164. This 
acid is of the same class with chloric, bromic and nitric acids. 
It is a solid body, very soluble in water and even deliquescent; 
soluble in nitric and sulphuric acids, from which solvents it may 
be separated in crystals. It forms with the alkalies and other 
bases, a class of deflagrating salts called Iodates. 

The superior affinity of iodine for oxygen enables it to decompose the 

288. Sources from whence iodine is obtained. 

289. Mode of obtaining iodine. 

290. (’omponent parts and equivalent of iodic acid. Properties. Io¬ 
dates. Formation of iodic acid. 

11* 


the iodine is extracted. 
Fig. 45'. 









122 


INORGANIC CHEMISTRY. 


oxide of chlorine, and form iodic acid; at the same time, the chlorine 
combines with another portion of iodine to form chloriodic acid. The 
latter body being exceedingly volatile, is easily separated by a gentle 
heat. Iodic acid is otherwise obtained by boiling iodine in nitric acid, by 
which means the latter is decomposed and furnishes oxygen to the 
former. 

291. Iodons Acid, is another compound of oxygen and iodine, which is 
proved to exist, but has never been indisputably obtained in a free state. 
There is probably, still another oxide of iodine, containing even less 
oxygen than iodous acid. 

292. Chloriodic J3cid. 1 Iod. 124, added to 2 ch. 72=196. This is a 
combination of chlorine and iodine, and is procured by passing chlorine 
gas into a dry bottle which contains iodine. It is solid, of an orange 
yellow color, very volatile, very soluble in water and deliquescent. Its 
solution is strongly acid; but when an alkali is added, instead of forming 
a chloriodate, we obtain a muriate and an iodate. This is owing to the 
decomposition of water ; the oxygen of which combines with iodine and 
the hydrogen with chlorine. The iodic and muriatic acids thus formed, 
take each its portion of the alkali. 

Bromine and iodine act on each other exactly as chlorine and iodine 
do, and produce a perfectly analogous compound called Bromide of iodine. 


FLUORINE.* 

293. Fluorine has never been obtained in a free state owing, as is 
supposed, to its very energetic affinities for other substances. It 
is one of the constituents of fluor spar , from which mineral the 
compounds of fluorine are commonly obtained. It is considered 
an electro-negative body, as possessing intense affinities for sim¬ 
ple substances, and forming with hydrogen, an acid called hydro¬ 
fluoric , 

294. Hydrofluoric Acid . This acid is obtained by heating a 
mixture of sulphuric acid and powdered fluor spar. 

* Silliman remarks, and we think justly, that “ it appears premature to 
place fluorine, a principle purely hypothetical, along side with chlorino 
and iodine, whose distinct existence and peculiar energy are manifested 
in so many remarkable forms.” We have followed the examples of 
most writers in giving fluorine this place though sensible of its doubtful 
claim. 


291. Iodous acid. 

292. Composition of chloriodic acid. How procured ? Properties, 
Bromide of iodine. 

293. Why is it supposed that fluorine has not been obtained in a sepa¬ 
rate state P From what mineral are its compounds obtained; supposed 
properties of fluorine. 

294. How is hydrofluoric acid obtained ? 



-FLUORINE. 


123 


The mixture must be made in a metallic 
retort (on account of the peculiar action of 
the acid on glass) and the vapor of hydro¬ 
fluoric acid must be received in a close 
vessel c, of one of those metals. The va¬ 
por passing through the tube b into the 
receiver, which is kept cool by ice or 
clothes wet in cold water, is condensed 
into a liquid. This is hydrofluoric acid, 
and must be preserved in a closely stopped 
metallic bottle. 

295. Hydrofluoric acid, in the liquid 
state, is very volatile, giving oft’ dense white fumes if exposed in 
an open vessel, at the temperature of 60° F. Its specific gravity 
when pure, is but little above that of water; but when com¬ 
bined with some water, it forms a less volatile hydrate of the 
specific gravity of about 1.25. This acid has an affinity for wa¬ 
ter, even much greater than that of sulphuric acid. In combin¬ 
ing with water, it produces very great heat, and causes a hissing 
like that produced when hot iron is quenched. It corrodes ani¬ 
mal and vegetable bodies more powerfully than any other sub¬ 
stance, producing a deep and dangerous ulceration when it is put 
on the skin. This action is the result of the powerful affinity 
the acid has for water. 

296. It also acts on glass, dissolving the siliceous matter of 
that substance and destroying its transparency ; or even perfor¬ 
ating it when a sufficient quantity of acid is used. 

By this aotion, two compounds are formed; the oxygen of the silex 
forms water with the hydrogen of the acid ; w T hile the silicon unites with 
the fluorine to form a colorless acid gas, called fluosilicic acid. 

This property of hydrofluoric acid affords means of etching or 
engraving on glass. The glass must be covered with a thin 
and uniform coat of wax, after which a figure is traced on it with 
a sharp steel point. If it be now exposed to the fumes of the 
acid, or wet with the liquid acid the glass will be corroded where 
the wax has been removed by the steel point, while the covered 
parts will be left untouched. 

297. With oxides, hydrofluoric acid acts variously, combining with 
some to form hydrofluatcs , and decomposing others, in which case, water 
and a fluoride of the metal are the result. It is a powerful solvent, dis¬ 
solving rock crystal, flint, and other siliceous matters, besides several 
other bodies which are not attacked even by nitro-muriatic acid. 

Sulphuric acid displaces this aci4 from any of the hydrofluates; and 

295. Jts affinity for water. Its tfcffects on animal and vegetable bodies. 

296. Action of hydro-fluoric acid on glass. Compounds formed by 
this action. Etching on glass. 

297. Action of this acid with oxides. Its solvent properties. Is dis¬ 
placed by sulphuric acid. 





124 


INORGANIC CHEftfISTRY. 


then the hydrofluoric acid can be detected by exposing glass to the 
fumes as they rise. 

298. Some Chemists are disposed to regard this acid, (instead of fluor¬ 
ine and hydrogen,) as a compound of fluorine and oxygen; called fluoric 
acid ; and all phenomena relating to it are capable of explanation under 
this view. Thus fluor spar may be considered nfluate of lime instead of 
a fluoride of calcium ; so that when sulphuric acid acts on this mineral, it 
may be supposed simply to combine with the lime and liberate fluoric 
acid. Some recent experiments, however, seem to yield conclusive evi¬ 
dence in favor of the first mentioned view of the subject, or that the acid 
in question is hydro-fluoric , consisting of fluorine and hydrogen. 

299. Fluoboric Acid was discovered by Gay Lussac and Thenard, in an 
experiment intended to prove that the acid we have described under the 
name of hydrofluoric acid is an oxacid. Boracic acid being a compound 
of Boron and oxygen, they endeavored by its aid, to obtain fluoric acid 
from fluor spar. If they succeeded, it would establish their opinion on the 
disputed point; for there being nothing present in the experiment but 
Boracic acid and fluor spar, both anhydrous,* there could be no hydrogen 
in the product. 

But instead of hydrofluoric, (or fluoric,) acid they obtained a new gas 
one which does not act on glass ; is very soluble in water, which it attracts 
so strongly as to produce dense white fumes in the air when the least 
moisture is present; and decomposes by water, forming boracic and hy¬ 
drofluoric acids, forming borate of lime remaining in the retort. The dis¬ 
coverers believed that a portion of the boracic acid united to the lime and 
liberated fluoric acid; and that the latter immediately combined with 
another portion of boracic acid, to form the fluoboric gas which is there¬ 
fore a compound of the two acids. 

The decomposition of the fluoboric gas by water, and the consequent 
deposition of boracic acid, they attributed to the superior affinity of wa¬ 
ter for fluoric acid, by which the latter was taken from its combination 
with boracic acid. 

300. According to Prof. Hopkins, the chemical changes in this experi¬ 
ment are as follows.—-“The two materials being mixed and heated 
strongly in an iron tube or retort, the oxygen of a portion of the boracic 
acid, combines with calcium to form lime and displaces fluorine ; the lat¬ 
ter combines with the boron, which has thus been deserted bv oxygen, 
and forms the fluoboric gas ; and, finally the remaining boracic acid 
unites with the newly formed lime and borate of lime remains in the 
retort. The fluoboric gas being a compound of the electro-negative 
fluorine with the electro-positive boron, when it is passed into water the 
fluid is decomposed ; its hydrogen unites with the fluorine, and its oxy¬ 
gen with the boron, forming thus, boracic and hydrofluoric acids, of which 
the latter is wholly dissolved, while much of the former is deposited. 

* Anhydrous signifies without any water, entirely dry. 

298. Theory which considers this as fluoric rather than hydrofluoric 
acid. 

299. Discovery of fluoboric acid. Nature of the gas obtained by Gay 
Lussac and Tbenard with boron and fluorine. Its attractions for water. 
Opinion of the discoverers of this gas respecting the changes which ac¬ 
company its formation. 

300. Prof. Hopkins’ view of the chemical changes in this experiment. 
Use of this gas as a test. Why this gas chars animal and vegetable 
bodies. 








FLUORINE. 


125 


The moisture of the air effects the same decomposition of this gas, the 
fumes being rendered quite opake by the particles of solid boracic acid. 
On account of the formation of these fumes, fluoboric gas is of use in 
testing the minutest quantities of vapor in gases. The strong affinity of 
this gas for water, enables it to char animal and vegetable bodies with 
their oxygen and hydrogen and thus developing their carbon. 

301. Fluoboric acid unites with alkalies forming salts called fluoborates. 
When potassium is heated in this acid, the fluorine combines with it, 
and boron is liberated ; the same decomposition occurs when potassium 
is heated with an alkaline fluoborate, which furnishes the best method 
for obtaining boron. 

This acid gas is always generated when boracic acid is brought into 
contact with hydrofluoric acid ; and, accordingly, an easier process for 
obtaining it, than the one given, (see § 299,) is to mix those two bodies 
in a retort and apply heat. Or it may be obtained by heating a mixture 
of boracic acid, fluor spar and sulphuric acid. The gas should be collec¬ 
ted over mercury. 

302. Fluo-silicic acid Gas , is a compound concerning the nature of 
which the same question may be raised, as in the case of fluoboric gas. 
It is generated when hydro-fluoric acid comes in contact with silex and 
may either be composed of fluorine and silicon (in which case the oxy¬ 
gen of the silex unites with the hydrogen of the acid,) or, it may be 
considered, as a compound of fluoric acid and silica. We shall treat of 
it under the first supposition. It may be obtained by mixing, in a retort, 
powdered fluor spar, fine sand, (or powdered glass, of which silex is a 
principal constituent,) and heating with a lamp. The gas is to be col¬ 
lected over mercury. 

303. It is colorless and transparent, a non-supporter both of respiration 
and combustion, and forms dense white fumes in moist air. Its affinity 
for water, enables it to corrode the skin and to char vegetable matter. 
The fluorine in this gas being saturated with silex, it does not attack 
glass. It is soluble to a great extent in water, but is decomposed by it, 
with formation of hydrofluoric acid, and of silex which is deposited. 
The decomposition, however, is not total; some silex remains in solu¬ 
tion; and constitutes with the hydrofluoric acid, what is generally con¬ 
sidered a distinct compound and called hydro-fluosilicic acid. If the 
watery solution be filtered to remove the deposited silex and then evap¬ 
orated, the vapor of hydrofluoric acid is expelled, and the original gas is 
given off unaltered ; but if the evaporation be performed without filtra¬ 
tion, the silex is redissolved, and the fluosilicic gas is reproduced. 

If this gas be passed into an alkaline solution the whole silex is de¬ 
posited, and a hydrofluate of the alkali is formed. 

304. The acidity of fluosilicic, and of fluoboric gas is by some, con¬ 
sidered doubtful. It can only be exhibited with the aid of water, in 
which case decomposition takes place, and other acid compounds are 
formed, to which alone the acid reaction might be owing. Accordingly, 
some Chemists consider these gases as only the per fluorides of boron and 
of silicon. 

301. Salts of this acid. Other modes of obtaining fluoboric acid. 

302. Nature of fluo-silicic acid gas disputed. When the gas is gen¬ 
erated. Composition. Flow obtained ? 

303. Properties. Formation of hydrofluosilicic acid. Effects of pas¬ 
sing this gas into an alkaline solution. 

304. Arguments against, and in favor of the acid nature of fluosilicic 
and fluoboric acids. 



126 


INORGANIC CHEMISTRY. 


The acid property, however, seems to be sufficiently established by the 
fact that these gases unite with gaseous ammonia and form solid com¬ 
pounds or salts. 

305. The hydro-fluosilicic acid unites with alkalies and other bases. 
Its combination with potassa is of difficult solubility, and therefore this 
acid is sometimes advantageously used to remove potassa from solutions. 


LECTURE XII. 

SIMPLE ELECTRO-POSITIVE SUBSTANCES. - (Not Metallic .) 


Hydrogen . Water. 


306. The Electro-Positive substances are divided into Non - 
Metallic and Metallic. 

The Non-Metallic , Electro-Positive , substances are, as follows, 
viz.: 


1 Hydrogen, 

2 Nitrogen, 

3 Carbon, 

4 Boron, 


5 Silicon, 

6 Phosphorus, 

7 Sulphur, 

8 Selenium. 

' : > f ■ 


Hydrogen and Nitrogen are gases : Carbon, Boron and Silicon, 
have strong analogies to each other, being dark powders, insolu¬ 
ble, infusible and fixed, scarcely affected by acids, and forming 
weak acids by oxidation. Phosphorus, Sulphur and Selenium 
are solids, very fusible and volatile, and easily combustible, pro¬ 
ducing strong acids by combination with oxygen. All these 
have affinities for the electro-negative bodies, and are found at the 
negative pole where compounds of them and the electro-negatives 
are decomposed by galvanism. They have, also, more or less 
tendency to unite with each other. Several of them, among 
which sulphur is prominent, combine with the metals. 

307. Hydrogen. This gas is so named from the Greek hudor, 
water and gennao , to generate, because it enters largely into the 
formation of water. It was formerly called inflammable air from 
its combustible nature and phlogiston , from the supposition that it 
was the matter of heat. It is one of the most important of all 


305. Affinities of hydrofluo-silicic acid. 

306. How are the Electro-positive substances divided? General char¬ 
acteristics of these bodies. 

307. Equivalent of hydrogen. Meaning of the name. Synonymes. 
Where existing. Discovery of its elementary character. 





HYDROGEN. 


127 


the inflammable substances; existing in nature in a variety of 
combinations, and forming invariably a constituent of water. 
Mr. Cavendish, in 1766, first ascertained the nature of this gas 
as a distinct elementary substance, and experimented upon its 
properties. 

308. Hydrogen gas is obtained by the decomposition of water, 
which may be effected in several ways. We shall first describe 
the process of decomposing water by Galvanism. 

Fig. 47. 

Let the two poles* of the voltaic 
pile, be immersed in a vessel of 
pure water; the liquid will be de¬ 
composed ; oxygen will be given 
off at the positive pole, D, and 
hydrogen at the negative pole N. 
The gases may be collected by 
inverting over each pole a glass 
tube O, and H, closed at one end, 
and filled with water. 

As opposite electricities attract 
each other, the oxygen is consid¬ 
ered as electro-negative, and hy¬ 
drogen electro-positive ; and thus 
these two gases are placed at^the 
head of their respective divisions. 

Hydrogen may also be obtained 
by decomposing water with red hot 
iron. For this purpose, iron wire coiled up is put into a gun barrel, c, 
open at both ends. The gun barrel is then passed through a furnace. 
To one end of the iron tube or gun-barrel is luted the neck of a retort, A, 
containing water ; and to the other, a bent tube, E, of iron wire. A fire 
is now lighted in the furnace, and the water in the retort is boiled by 
means of an argand lamp. The steam of the boiling water is decomposed 
in passing through the coil of iron wire in the gun barrel ; the oxygen 
combines with the iron which is found to be converted into the black 
oxide of iron; the hydrogen passes off into the receiver, G. 

Hydrogen may be obtained with a very simple apparatus, by the aid of 
an acid. Dilute some sulphuric acid with 8 or 9 times its bulk of water, 
and pour it into a retort, or bottle containing pieces of zinc or iron.t A 
violent effervescence will immediately ensue, owing to the escape of hy¬ 
drogen gas, which is always to be received over water. 

* The wire used for the poles should be of platinum, as the oxygen 
would combine with iron wire. 

1 The great heat evolved by mixing sulphuric acid and water would en¬ 
danger the vessel without due care. The acid should be gradually pour¬ 
ed into the water; not the water into the acid. 

308. From what substance is hydrogen usually obtained ? Decompo¬ 
sition of water by galvanism. Decomposition of water by heated iron. 
Decomposition of water by sulphuric acid. Explained on the theory of 
disposing affinity. 










128 


INORGANIC CHEMISTRY. 


Fig. 48. 



u This last decomposition,” says Prof. Hopkins, “ can only be satis¬ 
factorily accounted for by the theory of disposing affinity ; an hypothesis 
which has been too hastily rejected by some, who are, nevertheless, ob¬ 
liged to use it in explaining many phenomena. According to this theory, 
the presence of a particular body A, may determine the formation of 
another body B, for which A has an affinity, under circumstances where 
B would not be formed, but for the presence and disposing affinity of A. 
There are numerous instances of this, among which is the decomposition 
now under consideration. The metal becomes oxidized at the expense 
of the water whose hydrogen is evolved. The newly formed oxide unites 
with the sulphuric acid, forming sulphate of iron, (green vitriol,) or 
sulphate of zinc, (white vitriol,) according as iron or zinc is used. Now, 
neither iron nor zinc can decompose water at common temperatures; 
sulphuric acid has a strong attraction for the oxide of each metal, and this 
disposing affinity assists the natural affinity of the metal for oxygen, 
causing what would not otherwise take place, the decompositiop of wa¬ 
ter and oxidation of the metal.”* 

309. Hydrogen gas is transparent and colorless, a powerful 
refractor of light, and very strongly electro-positive. As com¬ 
monly obtained, it has a faint, disagreeable odor, which, how¬ 
ever, does not belong to the gas, but to volatile oil mingled with 
it. It is used for filling balloons, being the lightest body known 
in nature. It is about 14 times lighter than atmospheric air, 
and 16 times lighter than oxygen ; its specific gravity, air being 
1. is 0.694. Hydrogen has never been reduced to the liquid 
state. It has resisted all attempts to resolve it into more simple 
parts, and is, therefore, considered an elementary body. This 
gas is scarcely absorbed in water ; it has neither acid nor alka¬ 
line properties. It is not poisonous, but an animal confined in it, 
dies for want of oxygen ; for the same reason; a burning body is 
extinguished on being immersed into this gas. 

* Dr. Turner remarks, that “ the only obscurity of this explanation 
arises from the necessity of describing changes as consecutive , which are, 
in reality simultaneous .” 

309. Properties of hydrogen gas. The elementary nature of hydro¬ 
gen, &c. Why an animal cannot live in an atmosphere of this gas, and 
why flame is extinguished in it. Experiment showing that hydrogen 
will not support combustion. 






























HYDROGEN. 


129 


A lighted candle placed under a jar of 
hydrogen gas, is extinguished, tliough by 
its flame it will set the gas at the mouth of 
the jar on fire, and may be re-lighted, by 
having the wick brought in contact with the 
flame, when the combustion goes on, be¬ 
cause there is oxygen to support it. 


310. Hydrogen is highly inflammable. Let some iron filings, 
water, and sulphuric acid, be put into a flask, and a jet of hy¬ 
drogen will soon issue from a tube fitted to the mouth of the 
flask ; this jet may be set on fire by a lighted taper ; and will 
burn suddenly, with a very faint greenish light. The color of 
the flame, however, appears to depend on impurities, as the 
flame of the purest hydrogen, is scarcely perceptible. If hydro¬ 
gen gas be mixed with oxygen in proper proportions, and then 
set on fire, the whole burns at once, with a loud explosion. 
The detonation takes place also, but not so violently, if air be 
used, instead of oxygen gas ; the proportions for producing the 
most powerful explosion, are two measures of hydrogen, to one 
of oxygen, or five of air. These explosive mixtures may be 
kindled, not only by flame, and an ignited body, but also by the 
electric spark, and by platinum in that particular form called 
spongy platinum. If a jet of hydrogen gas be directed against a 
piece of spongy platinum, the latter becomes red hot, and sets 
fire to the stream of gas. Observation of this fact has given 
rise to the construction of an apparatus for procuring instanta¬ 
neous light by means of spongy platinum and hydrogen gas. 

311. The heat of the flame of hydrogen is very great, even 
when a jet of the gas is burned in the air ; but if the gas be 
previously mixed with oxygen, the quantity of caloric evolved, 
is greatly increased ; indeed, the heat of the flame thus produced, 

310 Inflammable nature of hydrogen. Experiment. Explosive and 
inflammable nature of hydrogen and oxygen. Hydrogen inflamed by 
spongy platinum. 

311. Heat of the flame of hydrogen. Increase of heat from a mixture 
of oxygen and hydrogen. Compound blow-pipe. Newman’s invention, 
and objections to it. Description of Dr. Hare’s blow-pipe. 

12 












130 INORGANIC CHEMISTRY. 

is generally considered the greatest that can be produced by 
artificial means. For the first application of this fact to useful 

purposes, science is indebted to 
Dr. Hare in the construction of 
the oxyhydrogen, or compound 
blow-pipe. In this apparatus, 
the gases are confined in separate 
reservoirs a a, from which they 
are expelled through tubes b 6, 
meeting in a conical piece c, in 
which the gases mix just before 
they are to issue. By this plan, 
all danger is avoided; for the ut¬ 
most that can happen, is the ex¬ 
plosion of the mixed portion of 
the gases contained in the coni¬ 
cal jet; a quantity too small to 
do any mischief. The flame of 
the compound blow-pipe, fuses 
the most refractory substances 
in nature. Platinum, which is quite infusible in the most pow¬ 
erful furnaces, is melted by it wilh great ease ; and even magne¬ 
sia is vitrified by it. This flame is not extinguished by water. 

312. The reason why the flame of the mixed gases is so much 
hotter than that of hydrogen, burning in an atmosphere of ox¬ 
ygen, will be obvious, if we reflect, that no combustible can 
burn, unless it be in contact with some other substance, which 
acts as a supporter of combustion. Now, when a column of 
the inflammable gas escapes into an atmosphere containing ox¬ 
ygen, only the surface of the column is in contact with the sup¬ 
porter, and consequently, only its exterior coat can burn. This 
being consumed, another layer of hydrogen is exposed, and 
burns in its turn; so that the column is constantly growing 
smaller as it rises, till at last it terminates in a point. Accord¬ 
ingly an ordinary flame, (as a candle or lamp, or the blaze on 
the hearth,) is conical, and a mere shell of ignited matter ; the 
interior consisting of unburnt, inflammable gas. In the com¬ 
pound flame, however, each part of hydrogen being already 
in contact with its particle of oxygen, the whole column is in 
combustion, throughout, its mass. The simple flame, therefore, 
bears to the compound one, the same relation that the surface of 
the cone bears to its volume. 


Fig. 50. 



312. Cause of the great heat of the mixture of hydrogen and oxygen 
gases. Difference between ordinary flame and that of the mixture of 
hydrogen and oxygen gases. 






































HYDROGEN. 


131 


COMPOUNDS OF HYDROGEN AND OXYGEN. 

313. Protoxide of Hydrogen or water, consists of 1 proportion 
of oxygen which is considered as 8, to 1 of hydrogen, which is 
considered as 1, the sum of the two being 9 : or to state the pro¬ 
portions as is customary in chemical works, 1 ox.8 added to 1 hyd. 
1=9. Whenever hydrogen is made to combine directly with 
ox yg en , either by explosion or otherwise, the compound formed, 
is water ; nor will any variation of the proportions in which 
they are mixed, cause the formation of any other product; and 
when either gas is in excess, that excess will remain unconsumed 
after the experiment. Thus, if two measures of each gas, be 
mixed in a proper detonating ^tube, over mercury, and fired by 
the electric spark, it will be found after the explosion, that three 
measures have disappeared, and that mercury has risen in the 
tube to supply their place. The remaining one volume, consists 
entirely of oxygen; so that the whole of the two measures of 
hydrogen, have combined with one measure of oxygen. If three 
volumes of hydrogen and one of oxygen, be exploded in the 
same manner, there will be a condensation of three volumes, and 
the residual volume will be hydrogen. 

314. There are various ways of showing the formation of 
water by the combination of hydrogen and oxygen gas. 

Experiment 1st. Hold a perfectly clean, and dry, glass vessel 
over a jet of hydrogen gas, the oxygen of the air combining with 
the hydrogen, will form an aqueous vapor, which will appear on 
the inner side of the glass. 

Experiment 2nd. Let a current 
of burning hydrogen pass into the 
mouth of the tube a, the glass cylin¬ 
der 6, will soon appear covered with 
dew from the condensation of the 
aqueous vapor, produced by the ox¬ 
ygen of the air uniting with the burn¬ 
ing hydrogen. 


313. Composition of water. Compound which results from the com¬ 
bination of hydrogen and oxygen. If either gas is in excess in a mix¬ 
ture which is exploded. What proportions, in volume, of these gases 
unite to form water. 

314. Experiment 1st., showing the formation of water by the combus¬ 
tion of hydrogen. 


Fig. 51. 









132 


INORGANIC CHEMISTRY. 


Fig. 52. 



Experiment 3 d. A more complicated apparatus for shewing 
the formation of water by means of the combination of oxygen 
and hydrogen was invented by the French chemist Lavoisier. 
a This apparatus consists of a glass globe, with a neck cement¬ 
ed into a brass cap from which three tubes proceed, severally 
communicating with an air pump, and with reservoirs of oxygen 
and hydrogen. It has, also, an insulated wire, for producing the 
inflammation of a jet of hydrogen, by means of an electric spark. 
In order to put the apparatus into operation, the globe must be 
exhausted of air, and then supplied with oxygen to a certain ex¬ 
tent. In the next place, hydrogen is to be allowed to enter in a 
jet, which is to be inflamed by an electric spark.”— Dr. Hare. 


Experiment 3d. By means of Lavoisier’s apparatus. 
































HYDROGEN. 


133 


Fig. 53. 



Experiment 4th. Let a be a glass cylinder, 
filled with pure oxygen ; 5, a bell glass contain¬ 
ing hydrogen, and partly immersed in a vessel 
of water, c. On opening the stop cocks, d d, 
the the hydrogen rises through the capillary 
tube /, and on being inflamed by an electric 
spark, it burns with great force, and drops of 
water soon collect in the cylinder. 

Analysis of Water. 



315. We have shown conclusively by syn¬ 
thetic proof that water is composed of two 
gases. By a reversed method , or that of anal¬ 
ysis, the same fact may be demonstrated with 
equal clearness. 

Experiment 5th. When water, in the state 
of steam, is made to pass over heated iron, the 
metal absorbs the oxygen, and hydrogen gas 
escapes. The iron will be found to have gain¬ 
ed in weight 8 grains of oxygen, for 1 grain 
of hydrogen obtained. 

Figure 54, shows an apparatus, invented by 
Dr. Hare, by which steam is decomposed by 
passing over hot iron. The gun-barrel to 
which the retort is cemented, is fitted at its 
opposite end with a flexible leaden tube, for 


Experiment 4th. 

315 Analytical proof of the composition of water. 

Experiment 5th. Analysis of water by means of an apparatus invent¬ 
ed by Dr. Hare. 

12* 










134 


INORGANIC CHEMISTRY. 


the purpose of con- 
Fig. 54. ducting off the hydro¬ 

gen gas. Within the 
gun-barrel is introduc¬ 
ed a quantity of iron 
turnings, or refuse 
card teeth. The glass 
retort is partly tilled 
with water. A quan¬ 
tity of charcoal within 
the furnace being ig¬ 
nited, soon heats the 
gun-barrel to a red, 
and then to a white 
heat. In the mean¬ 
time, a chafing dish 
of burning coal is 
placed under the re¬ 
tort ; the water soon 
boils, is changed to 
steam, which passes 
through the gun-barrel 
and parts with its oxy¬ 
gen to the metal, while 
the hydrogen escapes through the flexible leaden tube, and may 
• be collected. 

We have already shown, (308, Ex. 1st.) that when water 
is subjected to the action of the galvanic pile, it will be decom¬ 
posed, and hydrogen will appear at the negative, and oxygen at 
the positive pole. Let a glass tube be filled with water, corked 
at both ends, and the two wires of the galvanic circle, then put 
through the corks. The water being acted upon by galvanic 
electricity, its elements separate, hydrogen being attracted to 
the negative pole, and oxygen to the positive. 

316. The figure represents the com¬ 
parative bulk of the atoms of hydrogen 
and oxygen as they exist in water; the 
former being twice as large as the latter. 
This is ascertained by the bulk of the 
two gases as obtained by the decomposi¬ 
tion of water. 4s the weight of the 
atom of oxygen is found to be 8, while 
that of the atom of hydrogen is 1, it 
follows that the specific gravity of oxy- 

316. Comparative bulk of the atoms of hydrogen and oxygen. Spe-. 
cific gravity of oxygen compared with hydrogen. 


Water. 


Hydrogen 

Oxygen 

8 

1 



Chem. Equiv. 9, 














HYDROGEN. 


135 


gen is sixteen times greater than that of hydrogen ; so that if its 
ultimate atom have the same bulk as that of hydrogen, its com¬ 
bining number would be sixteen instead of eight. 

317. Water, as obtained from the usual sources, is impure. Rain water 
collected at a distance from buildings, is less impure than that from 
springs, or that which has fallen from the eaves of houses, but still con¬ 
tains several gases, the odoriferous matter of plants, with traces of ani¬ 
mal and saline matter . The animal and vegetable matter contained in 
rain water, causes its tendency to putridity. Spring and river water, in 
addition to the same impurities which exist in rain water, contain sever¬ 
al salts which they acquire from the soil, and of which sulphate of lime 
is one of the most frequent. To these salts water owes the property 
commonly called hardness ; that is, the property of decomposing soap, 
(or of curdling it, as it is usually termed }) for soap, is in reality, a salt, 
being composed of acid and alkali; so that when it meets an earthy salt 
in solution, a double decomposition ensues; the soap and the other salt 
exchange acids, and two new salts are formed, one of which is curdy, 
and floats on the surface of the water. An alcoholic solution of soap is, 
therefore, a good test of the presence of earthy salts in water ; another 
test, is a solution of pearlash, which shows the presence of these salts, 
by producing a white precipitate, or at least, a cloudy appearance if 
dropped into water containing them. The white deposit on the inside 
of a tea-kettle, in which spring water has been much boiled, (when the 
kettle, in common language, is said to be furred,) is a mixture of carbon¬ 
ate and sulphate of lime. The spring water of some localities is harder 
than that of others, because some soils contain more of soluble salts than 
others. The presence of these saline substances, not only communi¬ 
cates a somewhat nauseous taste to water, but injures its solvent powers in 
some particular instances ; thus, it has been found that of equal portions 
of rain and spring water, the former will extract from a given portion of 
tea, a considerable greater quantity of its soluble matter than the latter. 

318. The gaseous and other volatile bodies contained in water, may be 
expelled by boiling it; they also partially escape, when water freezes, so 
that water in sufficient purity, for many purposes, may be obtained by 
melting fresh fallen snow. Such water is flat, tasteless and insipid ; the 
liveliness of water, in its ordinary state, being due to the gases it holds 
in solution. But the only way of obtaining perfectly pure water, is by 
distillation in silver vessels, in which process, the saline impurities re¬ 
main in the distilling vessel, while the water is converted into vapor and 
passes into the condenser* For extremely nice operations, such as 

* A coffee apparatus has been recently invented in France, by which 
that beverage is prepared of great strength and superior flavor. Its pe¬ 
culiarity consists in making the vapor of water pass through the ground 
coffee. The aromatic portion is thus extracted, with much less of the 
bitter principle, than in the usual method. The water being distilled 
before it comes in contact with tl*e coffee, all the impurities of the former 
are left in the bailer. 


317. Impurities of water. Rain water. Spring and river water. 
Cause of the hardness of water. Why hard water decomposes soap. 
Tests of the presence of salt in water. Cause of the white deposit on 
the inside of a tea-kettle. Why the water of some springs is harder thap 
Others. Why soft water is better for making tea than hard water. 




136 


INORGANIC CHEMISTRY. 


analysis, the water should be twice distilled, and must be preserved in 
bottles very closely stopped ; for if exposed to the air, it would again ab¬ 
sorb gases. 

319. Pure water is transparent, colorless, tasteless and in¬ 
odorous : a non-conductor of caloric, an imperfect conductor 
of electricity, and a powerful refractor of light. It is the unit 
of specific gravity for solids and liquids, and is 828 times as 
heavy as air. At 212° F., the barometer standing at 30 inches, 
the water boils; it freezes at 32°, and in congealing, shoots into 
needle shaped crystals, which cross each other at angles of 60 
and 120°. 

320. If the aeriform bodies that previously contained it, be expelled by 
boiling, it absorbs every gas, but in very different proportions ; some 
gases being dissolved in very minute quantities, while of others, water 
will take up several hundred times its own bulk. The quantity absorbed 
may be increased by pressure, and is in direct proportion to it; on remov¬ 
al of the additional pressure the excess of gas escapes with effervesence, 
as in the instance of common soda water. The gas contained in water 
under ordinary atmospheric pressure, is expelled by heat, or by remov¬ 
ing the pressure with an air pump. Water has a very extensive range 
of affinities, and is, therefore, an important chemical agent; it is the 
most general solvent we possess. 

321. Water enters into two kinds of combination besides solutions, 
and in these it unites in definite proportions ; these combinations exist 
1st, in crystals ; 2nd, in hydrates. 

1st. Many bodies in crystalizing form their solutions in water, carry 
with them a portion of water which constitutes an essential part of the 
crystal, and which cannot be separated without destroying its form and 
transparency. Water thus combined, is called water of crystalization. 
It is believed to be in a state of greater solidity in this combination than 
in the form of ice. It may be expelled by heat; and the crystal will 
then fall into powder. Some crystals, containing a large proportion of 
water, liquefy when heated, becoming dissolved in their water of crystal¬ 
ization ; they are then said to undergo the watery fusion; if the heat be 
continued, the water evaporates and the salt remains in a powder, or a 
shapeless mass. Alum is a remarkable example of this. Some salts in 
dry air, give up their water of crystalization and fall into powder; they 
are said to effloresce. Some salts, on the contrary, attract moisture from 
the air in such quantities, as to become dissolved in it; this property is 
called deliquescence. Salts and other bodies containing no combined wa¬ 
ter, are said to be anhydrous* 

* From two Greek words signifying icitliout water. 


318. Effect of boiling or freezing water in relation to its impurities. 
Distillation of water 

319. Physical properties of water. 

320. Absorption of gases by water. Effect of pressure on absorption. 
Solvent power of water. 

321. Compounds where water exists in definite proportions. Water 
of crystalization. How expelled. Watery fusion. Efflorescence. 
Deliquescence. Anhydrous salts. Hydrates. Liquid hydrates. Solid 
hydrates. Heat evolved in the slaking of lime. Are all hydrates de¬ 
composed by heat ? 



HYDROGEN. 


137 


2. Water exists in another class of compounds which are called hy¬ 
drates. Some of these are liquids ; for example, the strongest sulphuric 
acid of commerce contains an atom of water to an atom of acid, and is 
therefore a hydrate of sulphuric acid ; the strongest nitric acid, that can 
be produced consists of one equivalent of acid and two of water. Many hy¬ 
drates, however, are solid ; and the water they contain is in the greatest 
state of condensation in which it is known. Much caloric is consequent¬ 
ly evolved during the formation of hydrates ; thus, in the slaking of 
lime, which operation is in fact the conversion of pure lime into a hy¬ 
drate, the heat evolved, amounts to 800° F. Some hydrates are decom¬ 
posed by heat; but others retain the combined water at the highest tem¬ 
peratures. 

322. Deutoxide of Hydrogen . 2 ox. 16, to 1 hyd. 1=17. 
This is called deutoxide, because 2 atoms of oxygen combine 
with one of hydrogen, and sometimes the peroxide , it being the 
highest combination known of oxygen with hydrogen. 

This substance, cannot be formed by the direct union of the two gases. 
The only method at present known, is the oxidation of water by means 
of the ■peroxide of barium. In this process is added to water a portion of 
muriatic acid, and the peroxide of barium ; the latter, parting with oxy¬ 
gen, is reduced to a protoxide which unites with the muriatic acid, while 
the liberated oxygen unites with the water, converting it into oxygen¬ 
ated water ox deutoxide of hydrogen. Sulphuric acid is added to precipitate 
the protoxide of barium ; this it does by uniting to barium and forming 
a sulphate; the muriatic acid being thus freed,is now ready to act upon an¬ 
other portion of the peroxide of barium, and thus set free another por¬ 
tion of oxygen. But in order to set the muriatic acid free, and obtain 
the oxygenated water pure, other manipulations are requisite.* 

323 The deutoxide of hydrogen was discovered by Thenard 
in 1818. It is transparent and colorless, heavier than water, being 
1.452; it is volatile, inodorous, and of a metallic taste. It thick¬ 
ens the saliva, whitens the skin, and is, to a degree, caustic. It 
bleaches powerfully ; its oxygen being considered the active 
bleaching principle. It is very easily decomposed, either by the 
contact of other bodies or by heat; and can only be preserved by 
keeping it at a temperature of about 32° F. 

If heat be applied to it in its concentrated slate, half of its oxygen sud¬ 
denly escapes with a violent explosion, and the residual product is water; 
but if it be largely diluted with a known weight of water, heat causes a 
slow disengagement of oxygen gas which may be collected ; and in this 
way the deutoxide of hydrogen is analyzed. Acids, also, prevent the 
explosive evolution of oxygen. 

Most of the metals and many of the oxides, being thrown in a state of 

* See Thenard’s Tradtie dc chimie , and other elaborate works on this 
subject. 


322. Proportions of the deutoxide of hydrogen. Manner in which it 
may be formed. 

323. Discovery. Properties. Decomposition. Effects of heat upon 
it. Its action with metals and oxides. Its application to useful pur¬ 
poses. 



138 


INORGANIC CHEMISTRY. 


fine powder on the deutoxide of hydrogen cause it to explode. Some of 
the metals thus become oxidized, and others are not effected ; nay, some 
of the metallic oxides lose, instead of gaining oxygen by this experiment. 
The decomposition cannot, therefore, be accounted for by the affinity of 
the metals for oxygen ; nor has any satisfactory explanation of the phe¬ 
nomenon yet been offered. 

The deutoxide of hydrogen has not been applied to any of the arts, 
and at present is only interesting to the Chemist, as a peculiar and strik¬ 
ing illustration of the doctrine of definite proportions. 


LECTURE XIII. 

HYDRACIDS. 

324. A class of substances possessing acid properties are 
termed hydracids , (or hydro acids ,) because they contain hydro¬ 
gen as one of their elements. Acids are the most remarkable 
products obtained by the union of both oxygen and hydrogen 
with other bodies. And yet, these two gases, so powerful in 
their combinations with other bodies, and standing each at the 
head of two distinct electro-chemical classes, form by their natu¬ 
ral combination with each other, the mild, inoffensive compound, 
water, with no trace of acid properties whatever. 

Some of the oxacids or oxyacids, we have already noticed, as 
Chloric, Iodic, Bromic and Fluoric acids ; and as we proceed to 
consider the electro-positive bodies, we shall have occasion to 
describe other important acids formed by a combination of those 
bodies with oxygen. 

All acids are formed by the union of a substance called the 
base or radical, with an acidifying principle. In chloric acid, 
chlorine is the radical and oxygen the acidifier. 

325. Of the radicals of the hydracids, some are simple bodies, and 
others compound. All the simple radicals are electro-negative, ex¬ 
cept sulphur; and even that is so while in combination with other 
electro-positive bodies. The compound radicals are electro-positive in 


324. Why are the hydracids so named ? Products of the union of oxy¬ 
gen and hydrogen with other bodies, and with each other. The radical 
and acidifying principle of acids. 

325. Radicals of the hydracids. Electrical nature of the simple and 
compound radicals. Effect of water in decomposing compounds formed 
between electro-positive and electro-negative bodies. Change which takes 
place in the chloride of sodium when dissolved in water. How may the 
chloride of sodium, or binary compound of the radical and metal, be 
again obtained ? 




HYDRATES. 


139 


relation to oxygen and other substances of the same class, but go to the 
positive pole, (and therefore, are electro-negative,) when just separated 
from combination with hydrogen or a metal. So that as regards the part, 
they act in composition of a hydracid, they may all, (both simple and 
compound,) be considered as electro-negative. They all have feeble affin¬ 
ities for compound bodies, but powerful ones for the simple electro-posi¬ 
tive substances, and when their compounds with the latter are put into 
water, (provided they be soluble,) that fluid is decomposed, its oxygen 
unites to the electro-positive elements to form an oxide, and its hydro¬ 
gen unites to the electro-negative radical to form a hydracid. If the ox¬ 
ide thus formed be a salifiable base, it combines with the hydracid to 
form a salt; if the compound put into water be insoluble, no action 
takes place. Thus common salt is chloride of sodium; dissolved in 
water it is muriate of soda , muriatic acid being formed by the chlorine 
and the hydrogen of the water, and soda by the sodium and the oxygen 
of the water ; but chloride of silver is quite insoluble in water, and un¬ 
dergoes no change in it. When a salt of a hydracid has been thus formed, 
the binary compound of the radical and the metal may be again obtained, 
by evaporating the solution to dryness, and heating the dry mass to expel 
the water which is re-formed - . 

326. The compounds of metals with the radicals of hydracids are 
called Haloid bodies, from their resembling salts in- their characters and 
habitudes ; the name haloid being derived from the Greek hale , sea-salt 
and oidos , like. Indeed, as had just been stated, they appear to become 
salts on being dissolved. 

The five most important of the simple radicals of the hydracids are, 

1. Chlorine, 

2. Bromine, 

5. Sulphur 

Fluorine having never been obtained in a separate state, the compara¬ 
tive energy of its affinity for hydrogen is not ascertained. .Neither is it 
known whether it can combine with oxygen or not. The other four 
radicals, are placed in the above list according to the order of their affin¬ 
ities for hydrogen; so that chlorine will decompose hydrobromic, hydri- 
odic and hydrosulphuric acids, forming hydrochloric acid and liberating 
the other radicals ; Bromine acts in the same way with hydriodics and 
hydrosulphuric acids; and iodine with hydrosulphuric acid only. The af¬ 
finities of these bodies for oxygen, are in the inverse order of their attrac¬ 
tion for hydrogen : sulphur having the greatest, and chlorine the least 
affinity for oxygen. 

327. The hydracids may be obtained, by pouring strong sulphuric acid 
on certain compounds, of their respective radicals with a metal. The 
water, which even the strongest liquid sulphuric acid contains, furnishes 
hydrogen to the radical and oxygen to the metal; the metallic oxide 
thus formed, unites to the sulphuric acid and forms a sulphate, and the 
hydracid is left free. 


326. Haloid bodies. Five most important radicals of the hydracids. 
Order of their affinities for hydrogen. Their affinities for oxygon. 

327. Manner in which the hydracids may be obtained. Nature and 
constitution of the hydracids. Attraction of the gaseous hydracids for 
water. 


3. Iodine, 

4. Fluorine, 



140 


INORGANIC CHEMISTRY. 


The hydracids are all, in reality gases; those of chlorine, bromine and 
iodine contain equal volumes of the two constituents, united without any 
condensation, so that one volume of the radical and one of hydrogen 
constitute two volumes of the hydracid. The specific gravity of these 
three hydracids is therefore half the sum of the specific gravities of their 
constituents. The gaseous hydracids are generally heavier than air, and 
have strong attraction for water. Some of them are absorbed by that li¬ 
quid to the amount of several hundred times its bulk. During the for¬ 
mation of these watery solutions, condensation takes place, heat being 
evolved, and the liquid resulting is heavier than water. It is in this state of 
solution that the hydracids are used in chemical operations; heat will 
expel from the liquid the greater part of the gaseous acid. 

328. The hydracid gases are decomposed when electrified with the 
proper quantity of oxygen gas, water being formed and the radical set at 
liberty ; some of the metals also, decompose them with the aid of heat, 
uniting with the radical and liberating the hydrogen. 

The liquid hydracids, that is the solution of the gaseous acids, act dif¬ 
ferently on different metallic oxides; with some protoxides, the acid com¬ 
bines to form salts; with others, a mutual decomposition occurs, and wa¬ 
ter is produced, together with a binary compound of the radical and the 
metal; but, in such cases, the latter compound is insoluble. Some of 
the peroxides yield a portion of their oxygen to the hydrogen of the,acid, 
fowning water and eliminating the radical; and thus are reduced to the 
state of protoxides, which combines with the radical acid and form salts. 
The first process given for obtaining chlorine, (§ 262,) is an example of 
this decomposition. With some oxides the hydracids do not re-act in any 
manner. 

329. Hydrochloric or muriatic acid. 1 ch. 36, to 1 hyd. 
1=37. 

This hydracid is commonly called muriatic acid from the 
Latin muria , sea-salt. It was at first known under the names 
of marine acid, and spirit of salt, and was regarded as an oxa¬ 
cid, formed by the union of oxygen with an imaginary base, 
named muriatium. 

It is obtained by pouring strong sulphuric acid on chloride of 
sodium , (common salt,) contained in a tubulated glass retort, A, 
and applying heat as at C. The tube of the retort, B, passes 


328. Their decomposition. What are liquid hydracids, and how do 
they affect metallic oxides P 

329. Composition of hydrochloric acid. Synonyme. Origin of the 
name muriatic acid. Mode of obtaining hydrochloric acid. Rationale. 



HYDROCHLORIC ACID. 


141 




under a receiver fill¬ 
ed with mercury and 
inverted over a me- 
curial trough. 


The water of the 
sulphuric acid fur¬ 
nishes oxygen to the 
sodium, and hydro¬ 
gen to the chlorine ; 
the metallic oxide 
thus formed, (oxide 
of sodium,) unites 
with the sulphuric 
acid forming sulphate 
of soda, and the hy¬ 
drochloric acid being 


disengaged, passes through the tube of the retort into the receiver.* 
The dense white fumes which appear over the mercurial trough, 
are caused by the escape of some portion of the hydrochloric 
acid gas, which unites with the aqueous vapor of the atmos¬ 
phere. 

330. Hydrochloric acid is colorless, transparent, and of a pe¬ 
culiar odor. It is irrespirable when pure; but if diluted with 
air, may pass into the lungs, but, even in that case, it exerts a 
corrosive action on'them. Its affinity for water is great, a vol¬ 
ume of that fluid absorbing 480 volumes of the gas, and forming 
the liquid muriatic acid. 

331. The process of forming hydrochloric acid, is very conveniently 
performed, by an apparatus called, from its inventor, Woulfe’s appara¬ 
tus. The retort a, contains common salt and sulphuric acid; a gentle 
heat being applied, the muriatic gas is disengaged and passes into the 
globe or first bottle, i, which, with the other bottles, contains water. The 
first bottle serves to condense any vapor which may be mingled with the 
muriatic acid gas, and the liquid in this will then be an impure solution 
of muriatic acid. From the globe i, the purified gas proceeds through 
the bent tube to the next bottle, where a portion is absorbed by the wa¬ 
ter ; the excess of gas then passes on, and a portion is, in like manner, 
absorbed by the liquid. Should some portion of the gas escape absorp- 

* In the author’s Chemistry for Beginners, this process for the sake 
of greater simplicity is explained according to the theory which consid¬ 
ers common salt as muriate of soda, and the gas which is eliminated from 
it by the action of sulphuric acid, as muriatic acid. The theory stated 
in the text is however, more conformable to the present state of sci¬ 
ence. 

330. Properties. 

331. Mode of obtaining hydro-chloric acid by means of Woulfe’s ap¬ 
paratus. Why should the bottles be kept cool ? Further proof of the 
affinity of this gas for water. 


13 








142 


INORGANIC CHEMISTRY". 


tion, it may by the last tube be conducted under a receiver in the pneu¬ 
matic cistern. The number of bottles may be increased or diminished. 
The straight tubes c, c, c, are called safety tubes. While they oppose at¬ 
mospheric pressure to the escape of the gas, they prevent the vacuum 
which would ensue from a sudden absorption of the gas, and which 
might draw in the impure acid contained in the globe. 

Fig. 56. 


c c c 



During this absorption a great condensation takes place, and heat is 
consequently evolved ; so that the bottles used to contain the liquid 
must be kept cool by ice, in order that the solution may be saturated. 
As a further proof of the affinity of this gas for water, if a piece of ice be 
let up into a jar of the gas, it will be melted almost as rapidly as by a hot 
iron ; and the gas is absorbed by the water thus formed. w 

332. This gas possesses acid properties in a very high degree ; 
combining with salifiable bases, reddening litmus paper, &c. ; 
many of the metallic oxides react on it by the aid of heat, water 
and chloride of the metal being formed ; several of the metals 
also decompose it by means of their affinity for chlorine ; in such 
cases, a chloride of the metal is formed and hydrogen gas set 
free. 

Hydrochloric acid is the only known compound of chlorine 
with hydrogen. It is composed of equal bulks of chlorine and 
hydrogen gases united without any condensation. 

333. Aqua Regia , or Nitro-muriatic acid , is a mixture of nitric 
with muriatic (or hydro chlorine acid ;) it is used for dissolving 
gold and platinum. Soon after the acids are mixed, the liquid 
grows deeper colored, and, at last, becomes wine colored, and an 
evolution of chlorine is perceptible. On heating the mixture, 
chlorine and deutoxide of nitrogen are expelled, after which it no 
longer dissolves gold ; hence it appears that chlorine is the cause 
of its solvent property with regard to that metal. The proper 
proportions are two parts of muriatic acid to one of nitric. 

When chloric acid is mixed with muriatic acid a similar de. 
composition occurs; the oxygen of the former uniting with th e 

332. Acid properties of this gas. Action of metallic oxides and metals 
upon it. Composition in respect to volume. 

333. Aqua-regia or nitro-muriatic acid. Mixture of muriatic acid with 
chloric and some other acids. With nitrate of silver. 








HYDROCHLORIC ACID. 


143 


hydrogen of the latter acid, water is formed and the chlorine of 
both acids is liberated; the mixture then acquires the property 
of dissolving gold. 

334. Hydrobromic Acid Gas is composed of equal volumes of bromine 
vapor and hydrogen, united without change of bulk. In this, and in 
most other particulars it resembles muriatic acid. Thus it forms salts 
with some oxides, and is decomposed by others; it has a powerful affini¬ 
ty for water. Its odor is very nearly that of muriatic acid. It is obtain¬ 
ed by exposing bromine to the action of sulphuretted hydrogen gas, 
when the former takes the hydrogen, and sulphur is deposited; or, by 
mixing bromine, phosphorus and water in a small retort and applying 
heat; in which case, the pihosphorus and bromine join in decomposing 
water, the former taking the oxygen and the latter the hydrogen. 

335. Hydriodic Add Gas contains one volume in bulk of iodine vapor, 
and one of hydrogen gas, combined without alteration of bulk. It is 
consequently, constituted like muriatic and hydrobromic acid gases, 
which it also resembles in all its general properties ; being decomposed 
by the same agents and under the same circumstances. The analogy 
extends even to its odor and its solubility in water. As the affinity of 
iodine for hydrogen is less than that of either bromine or chlorine, those 
substances will each decompose hydriodic acid, forming the correspond- 
ing hydracid, and eliminating iodine. Hydriodic acid gas, may be made 
by bringing iodine into contact with sulphuretted hydrogen gas, when 
sulphur will be set free, and iodine will take its place ; but this process 
is not commonly to be preferred. The best way of procuring this gas, is 
to moisten a mixture of iodine and phosphorus, in a very small retort, 
and apply heat, collecting the gas over mercury. As in the formation 
of hydrobromic acid gas, the oxygen of the water is taken by the phos¬ 
phorus ; so in this case, the hydrogen combines with iodine. 

336. The solution of hydriodic acid gas in water, or liquid hydriodic 
acid, is best obtained by passing sulphuretted hy drogen gas into water in 
which iodine is held suspended; the oxygen of the water disengages the 
sulphur, and the hydrogen combines with iodine. After the brown color 
has quite disappeared, the solution should be heated gently, to expel any 
excess of sulphuretted hydrogen, and then filtered to separate the pre¬ 
cipitated sulphur ; it is then colorless, transparent and strongly acid. If 
this solution be exposed for an hour or two to the air, it absorbs oxygen, 
which forms water with the hydrogen ; iodine is set free, and gives the 
liquid a brownish tint, which gradually deepens, till the whole acid is 
decomposed. Nitric acid, or any oxidizing agent, will produce the same 
effect. 

337. We have treated of hydrofluoric acid , under the head of its radi¬ 
cal fluorine, as it seemed necessary to introduce explanations connected 
with it, in the commencement of that subject. Hydrosulphuric acid , will 
be considered under the head of sulphuretted hydrogen, the name by 


334. Composition of hydrobromic acid gas in respect to weight and 
volume. Resemblance to muriatic acid. How obtained? 

335. Composition of hydriodic acid gas. Its analogies with muriatic 
and hydrobromic acid gases. May be decomposed by them. Different 
modes of obtaining this gas. 

336. Liquid hydriodic acid. 

337. What other hydracids are there besides the hydrochloric, hydro¬ 
bromic, and hydriodic ? 



144 


INORGANIC CHEMISTRY. 


which it is usually distinguished. Hydrocyanic acid, is an hydracid of a 
very peculiar nature, but cannot be well understood, until after the com¬ 
position of its radical, cyanogen has been explained. 


LECTURE XIV. 


NITROGEN AND ITS COMPOUNDS WITH OXYGEN. 


NITROGEN. 14. 


33S. Nitrogen is a permanent gas, and constitutes nearly four 
fifths of the atmosphere in bulk. If a lighted taper be covered 
with a large tumbler, or bell glass, the combustion will soon 
consume the oxygen of the air, and nitrogen will remain. For 
experiments, nitrogen may be better obtained by burning phos¬ 
phorus under a bell glass inverted over water. The phosphorus, 
combining with the oxygen of the air, forms phosphoric acid, 
which appears at first in dense white fumes, but soon settles upon 
the surface of the bell glass, and may be rinsed off in the water. 
The oxygen being now absorbed from the air, the bulk of the 
residue will be found, when cooled, to be condensed,* and on 
testing its properties it will be found to be nitrogen. 

* The fact of this diminution of bulk is known by the water over 
which the bell glass is inverted rising higher in the glass than before the 
fuming of the phosphorus. 


338. State in which nitrogen exists. Gas which remains when the 
oxygen in an inclosed portion of atmospheric air is burned. Obtained 
for experiments. Objections to the use of carbon and sulphur. Obtained 
from animal matter. 


X 




NITROGEN. 


145 


Fig. 56. 

Dr. Hare has invented the 
apparatus here represented 
for obtaining nitrogen in large 
quantities. Phosphorus is 
placed in a cup suspended in 
a glass vessel. Water is in¬ 
troduced by means of the 
tunnel T. The bladder, B, 
gives room for the expansion 
of the air which takes place 
when the phosphorus is burn¬ 
ing. The nitrogen gas hav¬ 
ing been obtained by means 
of consuming the oxygen, it 
is expelled by pouring more 
water into the funnel, which 
taking its place in the lower 
part of the vessel expels the 
gas through the tube P, the 
stop cock being turned so as 
to admit it to pass. The gas 
is thus received into vessels 
for the purpose of experiment. 
Slight impurities consisting 
of carbonic acid, and vapor 
of phosphorus, may be re¬ 
moved by solution of caustic 
potassa, or lime. Several 
other substances, having 
affinities for oxygen will ab¬ 
sorb it slowly from air ; among these, are, protosulphate of iron, and the 
alkaline hydrosulphurets. Carbon and sulphur, do not consume the 
oxygen of the air so completely as phosphorus does, and the products of 
their combination are sulphurous and carbonic acids, which being both 
gaseous, would, therefore, remain mixed with the nitrogen, and require 
a separate process for removing them. Nitrogen is a constituent of ani¬ 
mal matter and may be obtained by its digestion in diluted nitric acid. 

339. Nitrogen is colorless, transparent, tasteless, inodorous, 
permanently elastic, and lighter than common air, its specific 
gravity being 0.9722; It does not support the combustion of 
burning bodies, neither will an animal live in it; but in neither 
of these cases, is it supposed to exert any positive action; the 
effects being due merely to the absence of oxygen ; as the 
innoxious substance, water, will extinguish flame or animal life 
by excluding the air, and consequently the oxygen which is 
necessary to support combustion and respiration. Indeed, ni¬ 
trogen seems to possess no active properties, and can only be 
described by negatives. It tends to combine principally with 

339. Its physical properties. Is not a supporter of combustion. Its 
affinities not energetic. Why its compounds are easily decomposed. 

13 * 








146 


INORGANIC CHEMISTRY. 


the electro-negative bodies ; but even these affinities are not 
very energetic. Thus, though it combines under certain cir¬ 
cumstances with oxygen, chlorine, or iodine, it does not exert a 
direct action on them when mixed. 

As might be expected from its weak affinities, its combina¬ 
tions are generally decomposed with great facility ; the chloride 
and iodide of nitrogen, are decomposed with loud explosion by 
friction, slight increase of temperature, or the contact of other 
bodies. Water absorbs only a minute portion of this gas. It 
has a peculiar affinity for caloric and is an ingredient in most of 
the powerful fulminating compounds. 

Nitrogen was discovered about the year 1770, by Dr. 
Rutherford of Edinburgh, and Scheele of Sweden. It was at first 
called mephitic gas , or non-respirable air, and afterwards by the 
French Chemists, named azote, (from the Creek, a , to deprive 
of, and zoe , life ) The latter name implies active properties, 
such as this gas does not possess. For the name azote, has been 
generally substituted that of nitrogen, from the Greek word 
gennao to produce, combined with nitro, signifying to produce 
nitro, or nitric acid. 

Atmospheric Air. 

340. The atmosphere is a mass of gaseous matter which sur¬ 
rounds the earth and accompanies it in its revolutions. It pos¬ 
sesses weight, upon which fact depends the action of the sucking 
pump, the barometer, and the support of water or mercury in an 
inverted bell glass above the level of the exterior liquid. 

On weighing a glass flask full of dry air, exhausting it carefully and 
weighing again, it will be found to lose weight by the exhaustion in the 
proportion of 30 1-2 grains for every 100 cubic inches of air withdrawn, 
this being when the barometer stands at 30 inches, and the thermometer 
at 60° Fahrenheit. It is, therefore, 831 times as light as water, and 
about 11260 times as light as mercury. Air is taken as the unit of spe¬ 
cific gravity for aeriform bodies. 

341. From the observations of Dr. Wollaston and others, it seems to 
be established that the atmosphere is limited; and its extent is estimated 
at about 45 miles. As the air is more and more rare, as the distance from 
the earth increases, and as its expansive force decreases in the same ratio 
as its density it follows, that there must be a point at which its elastic 
force is just counteracted by the earth’s attraction. If the atmosphere 
were to expand without limit into space, the sun and the other planets 
would attract a portion of it to themselves, and would have atmospheres 
of the same kind as ours; a circumstance which is quite inconsistent with 
astronomical observation. Dr. Wollaston, from a series of observations, 

340. Nature of the atmosphere. Its weight. 

341. Limited extent of the atmosphere. Dr. Wollaston’s argument 
drawn from the limited extent of the atmosphere respecting ultimate 

. atoms. 



NITROGEN. 


147 


considers that this extreme rarefaction might take place, but for the fact 
that the atmosphere consists of indivisible ultimate atoms, that can be no 
farther rarefied. 

342. The atmosphere is highly elastic and compressible. 
When the pressure upon a confined portion of it is doubled, it 
will be reduced to half its original bulk ; or, if half the original 
pressure be removed, it will expand to double its former bulk ; 
in other words, its density is directly as the pressure , and its 
bulk in the inverse ratio to that pressure. This law is good 
also, for all aeriform bodies, so long as they continue in the aeri¬ 
form state. 

343. The temperature of the air is lower as we ascend, for as it must 
absorb caloric in order to expand, and this can be derived from no exter¬ 
nal source, it must render latent its own sensible heat; for radiant caloric 
passes through gaseous and aeriform media, without affecting them; so 
that the higher strata of air, though nearer the sun, derive no heat from it. 

The decrease of temperature is estimated at about one degree for every 
300 feet; so that there is, in every latitude, some point in the atmosphere 
at which ice never melts. This point at the equator, is about 15207 feet 
from the earth’s surface; and the distance decreases gradually toward 
the poles, where it is at the earth’s surface. 

344. The atmosphere is essentially composed of nitrogen and 
oxygen gases. Many other bodies are found in it, such as car¬ 
bonic acid, watery vapor, the odoriferous matters of plants, &c. 
&c.; of these, the first two are the most constant, and in the 
greatest quantity ; but even they vary in their proportions, which 
are never so large, compared to the whole mass, as to allow us 
to consider these bodies otherwise, than as accidental impurities. 
The carbonic acid is never more than 6.2 parts in 10.000 of air. 

Eudiometry. 

345. After the discovery of oxygen, it was for some time believed, that 
the proportion in which it was contained in the atmosphere, varied at 
different times and places ; and that the salubrity of a place, depended 
on the quantity of oxygen in the air around it. Hence the analysis of air 
was called “ Eudiometry,” or the “ measurement of quantity,” and this 
name has been retained, though the supposition from which it arose, has 
been shown to be false. 

Many eudiometers have been invented. They consist, in general, of 
tubes adapted to an apparatus for absorbing, or consuming the oxygen of 
a given quantity of air, and for measuring the residuum. The purity of 
the air is estimated by the quantity of oxygen which it is found to con¬ 
tain. Various substances which will absorb, or disengage the oxygen 
from a confined portion of air, and neither mix with, nor affect the vol¬ 
ume of nitrogen, have been used in eudiometry. But the only analysis 

342. Elasticity and compressibility of the atmosphere. Temperature^ 

343. Gradual decrease of temperature. 

344. Composition of the atmosphere. 

345. Origin of the term eudiometry. Construction and use of eudi¬ 
ometers. 



148 


INORGANIC CHEMISTRY. 


of air susceptible of perfect accuracy, is founded on the constancy of the 
proportion in which oxygen and hydrogen unite when burned together. 

346 If we put into a strong tube inverted over mercury, five measures 
of dry air, and add to this, two measures of pure and dry hydrogen gas, 
and then explode the mixture by the electric spark, or otherwise, we 
shall find after the tube has cooled, that just three measures have dis¬ 
appeared, and that the mercury has risen to fill their places. Now of 
these three measures, two we know to be hydrogen; and we also know 
that two measures of hydrogen, by explosion, condense one measure of 
oxygen. If we add more hydrogen to the residual four measures of gas, 
we can no longer produce an explosion; whereas, if we had not origin¬ 
ally added enough hydrogen, there would still have remained an excess 
of oxygen after the experiment. 

347.Five measures of air, then, contain exactly one measure ofoxj'gen; 
and the remaining four measures, on examination, will prove to be nitro¬ 
gen. This is the composition of atmospheric air; and the same unvary¬ 
ing result has been obtained at whatever season, height, or latitude the 
air may have been collected for experiment. So that it may be consider¬ 
ed established that the atmosphere, throughout its whole mass, consists 
of nitrogen and oxygen gases in the proportion of 80 per cent, of the 
former, and 20 per cent, of the latter. 

Fig. 58. The apparatus for performing the analysis, has been 
made in various forms. It is always, essentially, however, 
a strong glass tube a, open at one end ; and perforated 
,near the closed end, by two metallic wires b b , of which 
^the points are opposite and within one tenth of an inch of 
each other. These wires are for passing an electric spark 
into the mixture of gases. Dr. Hare recommends a con¬ 
tinuous, fine, platinum wire, instead of the two metallic 
points. This wire being ignited by means of a calorimoter, 
the gaseous mixture explodes. 

348. The atmosphere is generally regarded as a mechani¬ 
cal mixture of the two component gases. Some, however, 
prefer the supposition, that it is a chemical compound. 
The reasons for the latter opinion are, briefly, 

1. That the proportions of nitrogen and oxygen are every¬ 
where the same ; whereas, if it were a mere mixture, the 
heavier gas would be found most abundantly, in the lower 
strata. 

2. The proportions are definite, and accord with the numbers estab¬ 
lished as the atomic weights of oxygen and nitrogen ; agreeably to which, 
the atmosphere consists of two atoms of the latter to one of the former. 

But the investigations of Mr. Dalton, and especially of Dr. I. K. 
Mitchell of Philadelphia, have proved, that gases have a strong tendency 
to diffuse themselves through each other, contrary to gravity, and in 
spite even of the interposition of a bladder or thin sheet of india rubber ; 
and this, too, when no chemical affinity can be supposed to exist between 


346. Manner in which the constitution of the air may be demonstrated. 
Proportions of oxygen and nitrogen contained in it. These proportions 
do not vary. 

347. Apparatus for analyzing the air. 

348. Objections to the theory that air is a chemical compound of the 
gases, and not a mere mechanical mixture. Answer to these objections 
and arguments in favor of the theory. 
















NITROGEN. 


149 


them. If we fill a phial with hydrogen gas, and another with carbonic 
acid gas, connect them only by a capillary tube, and place them so that 
each gas shall be in its natural position, viz., the light hydrogen above, 
and the heavy carbonic acid below; it will be found after some time, 
that the carbonic acid has ascended, and the hydrogen descended, con¬ 
trary to gravity in each case ; and that the gases are equally mixed in 
both phials. In this case, no chemical affinity has been supposed to 
exist between the gases operated on. 

Furthermore, the facility with which bodies possessing affinities for 
oxygen, attract it from the atmosphere, is too great to admit the belief 
that it is chemically combined there. Again, the specific gravity and 
refracting power of the air, are arithmetical means between those of ni¬ 
trogen and oxygen; whereas, in cases of chemical combination, these 
two properties seldom escape alteration. And lastly, by merely mixing 
the two gases in the proper proportions, we can imitate the atmospheric 
air perfectly; whereas, it is only with great difficulty that we can make 
them combine, so as to produce one of the undoubted compounds of ni¬ 
trogen and oxygen. It seems, therefore, highly probable that the at¬ 
mosphere is a mere mixture of its components. 

340. The oxygen of the air is the active constituent; to it are owing 
the agencies of air in supporting combustions and respirations, and in 
most of the chemical changes in which it is concerned. The use of the 
nitrogen is not fully ascertained. It is generally held to be a mere dilu¬ 
ent, b^ means of which, the oxygen is prevented from stimulating the 
system too highly. There is, however, little doubt that some nitrogen is 
absorbed in the process of respiration. 

It might be supposed that the immense consumption of oxygen in com¬ 
bustions, respiration, spontaneous decompositions, and other operations, 
which are incessantly going on, would ultimately alter the proportions of 
the constituents of the atmosphere, to an extent that would render it 
unfit to perform its office. Doubtless this would be the case without 
some compensating circumstance. Only one such circumstance is known, 
and that is vegetation. It is ascertained that plants in the day-time, ab¬ 
sorb carbonic acid, of which they appropriate the carbon, and restore the 
oxygen to the atmosphere. In the night, the contrary process goes on ; 
the vegetables absorb oxygen and evolve carbonic acid. But it appears 
that the quantity of oxygen absorbed in the night, is less than that given 
out during the day ; so that vegetation tends to preserve to the atmos¬ 
phere its due portion of oxygen. Whether this cause is alone sufficient, 
or whether it is assisted by other sources of oxygen, is a question yet to 
be decided. 

On account of the doubt which exsists, whether air is a mechanical 
mixture or chemical compound of nitrogen and oxygen, we have treated 
of it under a separate head. All the certain chemical combinations of 
these two gases, are widely different in their properties, from this mild 
and inoffensive agent. 


349. Agencies of oxygen and nitrogen in the atmosphere. In what 
manner is it known, that air is replenished with oxygen, to make up that 
which it loses by combustion, respiration, &c. Do the other compounds 
of nitrogen and oxygen resemble atmospheric air ? 



150 


INORGANIC CHEMISTRY. 


Chemical Compounds of Nitrogen and Oxygen. 

350. There are five compounds of nitrogen and oxygen all of 
which conform strictly to the law of multiple proportions. The 
three highest in oxidation are acids ; at the ordinary temperature, 
their natural form is that of liquids, exceedingly volatile, and 
uniting in all proportions with water. The other two are gases, 
neither acid nor alkaline, and with little affinity for water. The 
definite compounds of oxygen and nitrogen are the following, viz., 


Protoxide of nitrogen, 

Nitrogen 14 

added to oxygen 8 

Deutoxide of nitrogen, 

it 

14 

4< 

“ 16 

Hypo-nitrous acid, 

U 

14 

u 

“ 24 

Nitrous acid, 

U 

14 

cc 

“ 32 

Nitric acid, 

a 

14 

cc 

“ 40 


351. Protoxide of Nitrogen. This is the well known exhilara¬ 
ting gas , often called nitrous oxide. 

It is prepared, by heating nitrate of ammonia in a small glass retort, 
and may be collected over water, which should be warm, in order to pre¬ 
vent, as much as possible, the absorption of the gas. Care must be taken 
that the temperature does not rise above 500° F.; the melted salt should 
be kept in a state of uniform and moderate effervescence, till the whole 
disappears or enough gas has been collected. 

The rationale is as follows. Nitric acid and ammonia constitute the 
salt called nitrate of ammonia. Nitric acid consists of nitrogen, 1 equiv¬ 
alent, and oxygen, 5 equivalents. Ammonia contains nitrogen, 1 equiv¬ 
alent, and hydrogen, 3 equivalents. The 3 equivalents of hydrogen 
with 3 of oxygen form 3 of water ; and the remaining 2 equivalents of 
oxygen with the 2 of nitrogen, constitute 2 equivalents of nitrous oxide. 
So that if the heat be properly regulated, the only products are water and 
the gas required. 

352. Nitrous oxide gas is colorless, has an agreeable but faint 
odor, and a sweetish taste, and dissolves in about its bulk of wa¬ 
ter at 60®. Its specific gravity is about 1.5. In mixture with 
an equal bulk of hydrogen, it explodes violently on the applica¬ 
tion of flame or the electric spark. It supports the combustion 
of many substances, owing to the oxygen it contains ; and as a 
given bulk of this gas contains 2 1-2 times as much oxygen as 
an equal bulk of air, bodies burn in it with proportionate bril¬ 
liancy. Thus, a recently extinguished candle, of which the 
wick is still red hot, is relighted, on being plunged into a jar 


350. General remarks on the chemical compounds of nitrogen and ox¬ 
ygen. Names and constitution'of these compounds. 

351. Synonymes. How is the protoxide of nitrogen prepared P Ra¬ 
tionale. 

352. Properties. Why do bodies burn in this air with more brilliancy 
than in common air ? 




NITROGEN. 


151 


of protoxide of nitrogen, and burns with great splendor. Sul¬ 
phur and phosphorus previously ignited, burn much more rap¬ 
idly and brightly when immersed in this gas. The combustibles, 
in these cases, unite with the oxygen of the gas and set the 
nitrogen free. 

353. Exhilarating gas was shown by Davy to support respira¬ 
tion for three or four minutes, but no longer. Those who inhale 
it usually experience strong excitement, usually of an agreeable 
kind, with a rapid flow of ideas, and an irresistible propensity 
to laugh, dance, leap, and sing. It has been erroneously thought, 
that, by this test, the real dispositions of persons are developed ; 
but the grave sometimes become suddenly gay, the coward bold, 
the meek quarrelsome ; and it might as justly be said, that in¬ 
sanity exhibits the real propensities of a person, as that the influ¬ 
ence of this gas does so. Some instances have been known of 
instant and alarming insensibility produced by it.* 

354. Dentoxide of nitrogen , or nitric oxide. Most of the metals, 
and many other oxidable bodies take a portion of the oxy¬ 
gen from nitric acid when brought into contact with it. In all 
such instances, the nitric acid is reduced to some of the lower 
compounds of nitrogen and oxygen ; and, in a few cases it is en¬ 
tirely deprived of oxygen, so that pure nitrogen only remains. 
The degree of reduction depends on the comparative affinity of 
the metal for oxygen. In most cases, nitric oxide is one of the 
products, and in some, the only one. It is evolved when copper 
is acted on by nitric acid moderately diluted. If the operation 
be performed in the open air, the deutoxide of nitrogen which is 
evolved instantly combines with oxygen and produces nitrous 
acid, which appears in dense red fumes ; but if it be performed 
in close vessels, and in a retort, the beak of which is plunged 
under water, the production of red fumes only lasts till the oxy¬ 
gen of the air in the vessel is consumed ; after which, the nitric 
oxide comes over very rapidly, and may be collected under an 
inverted bell glass filled with water. 

* I have witnessed several cases of fainting and spasms in young fe¬ 
males after inhaling the exhilarating gas, and would never advise such to 
make this dangerous experiment upon themselves. 


353. Its power of supporting respiration. Effects on the human sys¬ 
tem. 

354. Action of oxidable bodies on nitric acid. 





152 


INORGANIC CHEMISTRY. 


355. Let some copper filings be 
put into a retort, (see figure 59,) 
and nitric acid be poured in at the 
tubulure ; place a lamp under the 
retort, the beak of the latter being 
immersed in water below the per¬ 
forated shelf which supports the 
inverted bell-glass. A violent ac¬ 
tion takes place between the cop¬ 
per and nitric acid, and the red 
fumes of nitrous acid, fill the re¬ 
tort and pass over into the pneu¬ 
matic tub where they are absorbed 
by the water ; after this, the oxy¬ 
gen in the retort being consumed, 
a colorless gas appears, which does not unite with water, but ascends 
into the bell-glass taking the place of the water with which it had been 
filled. 

356. Nitric oxide is known, also, under the name of nitrous 
gas. It is colorless ; its specific gravity is 1.04, and it is spar¬ 
ingly absorbed by water. When oxygen, either alone, or in 
mixture with other gases, is admitted to a jar containing nitric 
oxide, brownish red fumes appear immediately. These fumes 
which serve to distinguish this gas from all others, are nitrous 
acid vapor ; and are immediately absorbed by water. Nitric ox¬ 
ide forms feeble combinations with alkalies and alkaline earths ; 
but as it has no action on blue test paper, it cannot be considered 
an acid. It supports the combustion of charcoal and phosphorus, 
which burn brilliantly in it ; extinguishes a candle and burning 
sulphur. Hydrogen does not explode with it, but the mixture 
burns with a brilliant flame, of a greenish white color. In all 
cases of combustion in this gas, the combustible becomes oxi¬ 
dized, and nitrogen gas is liberated from the deutoxide. 

This gas cannot be inhaled on account of its causing a spas¬ 
modic closing of the glottis. It is partially decomposed by a red 
heat, or by a succession of electric sparks. Iron filings attract part 
of its oxygen and convert it into the protoxide. Potassium, 
when heated in it, takes all its oxygen and liberates its nitrogen, 
and therefore affords an accurate mode of analyzing it. 

357. As red fumes of nitrous acid, which are absorbed by water, are 
always produced when nitric oxide is mixed with atmospheric air, this 
property of nitric oxide is made use of in eudiometry, or the analysis of 
air, in order to ascertain the proportion of oxygen. As in two volumes of 
nitric oxide, a volume of the nitrogen is combined with one volume of 


355. Mode of obtaining deutoxide of nitrogen. 

356. Synonymes. Properties. This gas not an acid. Its effects on 
burning bodies. Cannot be inhaled. Decomposition. 

357. Eudiometry by means of action of the protosulphate of iron with 
nitric oxide. 






NITRIC OXIDE. 


153 


oxygen, occupying the same bulk as if merely mingled ;—to convert the 
nitrous oxide into nitrous acid, which consists of the same quantity of ni¬ 
trogen with two volumes of oxygen,one volume of oxygen must be added. 
Of course, if nitrous acid be the product, one third of the deficit produced 
would be the quantity of atmospheric oxygen present.* 

35S. Hyponitrous Acid. When a mixture of nitric oxide and 
oxygen is confined over mercury,with strong solution of potassa, 
the alkali is gradually neutralized ; the two gases combining to 
form hyponitrous acid which unites with the potassa. This acid 
has not yet been obtained in a separate state. On adding a 
stronger acid,the hyponitrous.is expelled from its combination with 
potassa, but is immediately resolved into nitrous acid and nitric 
oxide of nitrogen. 

359. Nitrous Acid. This acid, being exceedingly volatile, is 
usually seen in the form of a red vapor, and has, until recently, 
been described as a gas. It is properly a liquid, and may be ob¬ 
tained in that form, by heating nitrate of lead to a dull red heat. 
The receivers must be dry, and kept cool with ice or snow. The 
heat decomposes the nitric acid of the nitrate of lead, and resolves 
it into oxygen and nitrous acid. 

Nitrous acid is powerfully corrosive, of an orange color, pun¬ 
gent odor, and sour taste. It reddens litmus paper, and when 
added to solutions of the alkalies, seems to be converted into 
nitric acid, for the resulting salt is a nitrate, and not a nitrite. 
It boils at 82° Fahrenheit, and evaporates with very great rapid¬ 
ity, when exposed to air. When once mixed with air or other 
gases, it cannot be again liquefied without great pressure or 
intense cold. 

Nitrous acid can be obtained in the form of vapor, by mixing two meas¬ 
ures of deutoxide of nitrogen, with one of oxygen, in a glass vessel 
which has been dried and exhausted of air. The vapor cannot be kept 
over mercury, for it parts with oxygen to the metal; nor over water, for 
the liquid absorbs it. 

It unites with water in all proportions. A very weak solution is pale 
blue ; as more of the acid is gradually added, the solution passes through 
several shades of green and at last becomes oi'ange colored, like the dry 
acid. It is supposed that water at first decomposes nitrous acid, resolv¬ 
ing it into nitric and hyponitrous acids, and that the blue tint is due to 
the latter. After the water becomes saturated to a certain point, this 
decomposition ceases, and the nitrous acid begins to dissolve unchanged. 
At this period, the red color of the nitrous, with the blue of the hyponi¬ 
trous acid, produces the green. At last, the quantity of nitrous acid is 

* For a description of Dr. Hare’s apparatus for analyzing atmospheric 
air by means of nitric oxide, see Chemistry for Beginners, page 99. 

358. Production and evanescent nature of hyponitrous acid. 

359. Nitrous acid a volatile liquid. How obtained in the liquid form. 
Properties of liquid nitrous acid. Obtained in the form of vapor. Union 
of this acid with water. Changes of color in its solution. 

14 




154 


INORGANIC CHEMISTRY. 


such, that its color predominates over, and hides the other color en¬ 
tirely. 

360. Nitrous acid parts rapidly with its oxygen to combusti¬ 
ble bodies, metals, &c., oxidizing some with such rapidity as to 
set them on fire. It is commonly reduced to deutoxide of nitro¬ 
gen ; but in some cases of violent action, it is totally deprived of 
oxygen ; and in others, it is reduced to protoxide of nitrogen. It 
is totally decomposed by a red heat. 

361. Nitric acid is known in commerce under the name of 
aqua fortis. There are two kinds, the single, and double; the 
latter being twice as strong as the former. This acid is procured 
by mixing nitrate of potassa, or nitre, commonly called salt-petre 
with strong sulphuric acid, and distilling the mixture. The 
proportions differ in different manufactories, and the qualities of 
the acid obtained, vary accordingly. The least quantity of sul¬ 
phuric used, is half the weight of the nitric ; the largest, is an 
equal weight. 


Fig. 60. 


Experiment. Nitric acid 
on a small scale, may be 
procured with the appara¬ 
tus here represented ; a is 
a retort, containing pound¬ 
ed salt-petre and sulphuric 
acid, b, is a receiver com¬ 
municating with the ves¬ 
sel c. The lamp, d, serves 
for heating the retort; the 
stands, with sliding rings, 
e e, support the retort, 
lamp, and receiver. 

Rationale. Sulphurio 
acid decomposes salt-petre 
(nitrate of potassa,) by 
uniting with potassa ; the 
nitric acid being liberated 
passes from the retort in¬ 
to the receiver 6, and 
from thence into the bottle, c, and is absorbed by water, of which the 
bottle contains a small portion. On examining this water it will be found 
to be weak nitric acid. 



360. Inflammable nature of nitrous acid, and decomposition. 

361. Common name of nitric acid. How procured. Experiment- 
Rationale of this experiment. Manufacture of nitric acid for com¬ 
merce. 















NITROUS ACID. 


155 


Those who manufac¬ 
ture nitric acid for pur¬ 
poses of commerce, 
make use of large^iron 
retorts set in brick work, 
and communicating 
with receivers made of 
earthen ware, furnished 
with stop cocks, the 
last of which has a 
safety tube communica¬ 
ting with a vessel of 
water. 

362. The theory 
of the operation in 
the manufactory of 
nitric acid, is obvious, 
potassa, and sulphu¬ 
ric acid, a stronger substance than the nitric, the sulphuric acid 
combines with the potassa, and forms sulphate of potassa, exclud¬ 
ing the nitric acid ; which being vaporized by the heat is con¬ 
densed again in cool receivers. 

363. Nitric acid may be formed directly, for the purpose of demon¬ 
strating its composition synthetically as well as analytically, by passing 
electric sparks through a mixture of oxygen and nitrogen gases confined 
over a solution of potassa. It is believed that a portion of the native ni¬ 
trates owe their origin to the formation of nitric acid from the elements 
of air, by the electric discharge during thunder storms; this acid being 
carried to the earth by the rain, acts on the oxides and carbonates with 
which it comes in contact. 

364. Pure nitric acid is colorless and transparent. It is com¬ 
monly found of specific gravity 1.42. It gives off white fumes 
when exposed to moist air; unites with water in all proportions, 
evolving heat; is sour to the taste, reddens litmus paper and 
combines with salifiable bases to form neutral salts. It attracts 
watery vapor from the air. Its affinity for water enables it to 
melt snow very rapidly, by which liquefaction, great cold is pro¬ 
duced. Nitric acid becomes red and fuming, by much exposure 
to light; for that agent decomposes it, revolving it into oxygen 
gas which is evolved, and nitrous acid which gives the color. 
Deutoxide of nitrogen also decomposes it, taking part of its oxy¬ 
gen ; by which the nitric acid and the deutoxide are both brought 
to the state of nitrous acid. By red heat it is totally decomposed 
into oxygen and nitrogen gases. It also readily parts with oxy- 

362. Theory ofthe operation in the manufacture of nitric acid. 

363- Nitric acid formed by electricity. Supposed origin of some of the 
native nitrates. 

364. Properties of nitric acid. Decomposition by light. By deutoxide 
of nitrogen. By heat. Why a powerful oxidizing agent. Its effect on 
animal and vegetable substances 


Fig. 61. 



Nitre being a compound of nitric acid and 





























156 


INORGANIC CHEMISTRY. 


gen to most of the bodies which have an affinity for it, and is, 
therefore, a very powerful oxydizing agent, particularly useful 
in metallic chemistry. For this reason it increases the com¬ 
bustion of red hot charcoal; and also converts sulphur and 
phosphorus into sulphuric, and phosphoric acids. Tin, copper, 
iron filings, powdered zinc and some other metals are oxidized 
by it with very violent action ; and many other metals are rapid¬ 
ly acted on by it. 

Animal and vegetable substances are powerfully attacked by 
this acid, and some of them, such as volatile oils, are set on fire 
by the rapid oxidation. It stains the skin yellow, destroying the 
cuticle, and causes deep ulceration if not speedily removed. 
The caustic power of nitrate of silver, (lunar caustic,) is due to 
the acid which enters into its composition ; and the acid is oc¬ 
casionally substituted for the salt, as a caustic. In all these 
cases the nitric acid is deprived of a part of its oxygen, and is 
reduced either to nitrogen, or to the oxides of nitrogen ; gen¬ 
erally the deutoxide is the principal product. 

365. The salts of nitric acid all possess the power of impart¬ 
ing oxygen to other bodies by the aid of heat. Thus when char¬ 
coal, sulphur, metallic antimony, and many other bodies are 
powdered with salt petre or some other nitrate, and then thrown 
into a red hot crucible by small quantities at a time, a violent 
action takes place, the nitric acid is destroyed, and the metal or 
other combustible is oxidized. This is a powerful method of 
oxidation, called deflagration. Nitrates, chlorates, iodates and 
other salts which, possess this property, are called deflagrating 
salts. The rapid combustion of gun-powder, (which is a mix¬ 
ture of nitre, sulphur and charcoal,) and its power of burning 
where air is not present, are due to the nitre, which furnishes 
readily all the oxygen necessary for the combustion of the char¬ 
coal and sulphur. Nitrates are all decomposed by a full red 
heat, and some of them at a somewhat lower temperature ; the 
difference of heat required is owing to the affinity of some bases 
for acids being greater than that of others; those having the 
strongest affinities, hold the elements of the acid together more 
strongly than others, and require a higher heat for decomposition. 
The product into which the acid is resolved by this operation, 
depends on the heat employed. 

366. The nitrates are all soluble ; therefore this acid cannot be diluted 
by precipitation. The deflagration of the nitrates, when thrown on burn¬ 
ing coals, and the, evolution at the same time of nitrous fumes, will in 

365. Cause of the deflagrating power of the salts of nitric acid. De¬ 
flagration, and deflagrating salts. Cause of the rapid combustion of gun¬ 
powder. Decomposition of nitrates by heat. 

366. Tests of the nitrates. Indigo a test for nitric acid. 



AMMONIA. 


157 


many cases serve to distinguish them. If in solution, they may also be 
diluted by adding some muriatic acid, and then putting in some gold 
leaf. If nitric acid or a nitrate be present, aqua regia will be formed and 
the gold be dissolved. But this test will only apply when we are sure 
that neither chloric nor bromic acid is present; either of which would 
cause the gold to dissolve on adding muriatic acid. The gold leaf, also, 
must be free from copper ; commercial gold leaf, on account of the cop¬ 
per it contains, will be dissolved by either nitric or muriatic acid sep¬ 
arately. 

The most delicate of all tests for nitric acid is indigo, the blue color of 
which is destroyed by it, and converted into a yellow. The mode of ap- 
plying the test is to dissolve some indigo in cold, dilute sulphuric acid, 
and add enough of the solution to produce a distinct blue color in the 
separated liquor ; then drop in a little sulphuric acid to take away the 
base with which the nitric acid is combined; the nitric acid, being thus 
set free, acts on the indigo. 


LECTURE XV. 

NITROGEN AND ITS COMPOUNDS WITH HYDROGEN, CHLORINE 
BROMINE AND IODINE. 

Nitrogen with Hydrogen , or Ammonia . 

367. Ammonia. This gas consists of 3 atoms of Hydrogen with 
1 of Nitrogen. It is known by the names of u hartshorn ,” 
u volatile alkali ,” &c. It is a permanent gas, colorless, and 
transparent, of an irritating and pungent odor, and a burning and 
caustic taste. It cannot pass into the lungs by itself, but may be 
made to do so when largely diluted with air, and it is not then 
found to produce any injurious effects. If inhaled through the 
nostrils, it irritates them, and produces a flow of tears. Taken 
internally in small doses, in combination with water it corrects 
acidity in the stomach, and is used as a gentle stimulant. 

It combines with all the acids, neutralizing them and produc¬ 
ing a distinct class of salts, most of which are crystallizable and 
soluble. When ammoniacal gas is mixed with any gaseous acid, 
as the muriatic, carbonic, &c., dense white fumes appear, and 
the acid and ammonia combine to form a salt, which is deposited 
on the vessels as a white powder. Ammonia extinguishes burn- 

367. Composition and equivalent of ammonia. Synonymes. Proper¬ 
ties. Its combinations. White fumes of ammonia, how caused ? Effect 
of ammonia on burning bodies. Detonation. Decomposition by elec¬ 
tricity and heat. Specific gravity. 

14* 





158 


INORGANIC CHEMISTRY. 


ing bodies which are plunged in it. It will not burn in atmos¬ 
pheric air ; but a small jet of it burns in pure oxygen. When a 
lighted candle is put into it, the flame becomes yellow, and en¬ 
larged for an instant before it is extinguished, owing to a momen¬ 
tary combustion of ammonia. This gas may be detonated by 
the electric spark when in mixture with oxygen. The products 
of the detonation are water and nitrogen, with a little nitric acid. 
It is resolved into nitrogen and hydrogen gases by a succession 
of electric sparks, or by passing it through red hot tubes ; and 
the two gases occupy twice the bulk of the ammonia. By adding 
oxygen to the mixed gases and exploding by the electric spark, 
it is found to be composed of one and a half volume of hydrogen 
to half a volume of nitrogen, condensed to one volume ; or by 
weight, of 3 equivalents of hydrogen and 1 of nitrogen. Thus 
the chemical equivalent is, 3 hyd=3 add to 1 nit. 14=17. Its sp. 
gr. is .59 or more than half that of air. 

368. Ammoniacal gas is brought to the liquid state by a pres¬ 
sure of 6 1-2 atmospheres, or about 97 pounds to the square inch. 
The alkaline properties of ammonia are well marked. It turns 
the yellow color of turmeric paper brown ; but as the ammonia 
soon evaporates, the yellow color is restored. The salts of 
ammonia are differently affected by heat. If the acid they con¬ 
tain is naturally a gas, as the carbonic, muriatic, and the like, the 
salt is sublimed without any change. If the acid is volatile, but 
only at a considerable heat, as the sulphuric, ammonia is expel¬ 
led at first, and then the remaining salt is sublimed. If the acid 
is fixed in the fire, (or not volatile,) as the boracic and phos¬ 
phoric, the whole ammonia is expelled and the acid remains. If 
the acid be one which is easily decomposed by heat, as the nitric, 
more complex decompositions ensue. 

369. Although ammonia is a strong alkali, its elasticity favors the de¬ 
composition of its salts ; so that they are decomposed by any of the fixed 
alkalies, or by the alkaline earths. This fact furnishes means of pro¬ 
curing ammoniacal gas. The materials commonly used are muriate of 
ammonia,, (sal ammoniac,) and slaked lime. The odor of ammonia is per¬ 
ceived as soon as the materials are mixed in a mortar. The proportions 

368. Liquefaction of ammonia. Its alkaline properties. Effects of 
heat on its salts. 

369. Decomposition of the salts of ammonia. 




AMMONIA. 


159 




Fig. 62 . 


used are equal weights of the two arti- 
cles. On heating this mixture in a 
glass retort, the gas comes over abun¬ 
dantly mingled with watery vapor. 
To separate the latter, there should be 
an intermediate receiver containing 
fragments of caustic potassa, or chlo¬ 
ride of calcium. If the latter is used, 
some of the gas will be absorbed as well 
as the watery vapor. The dried gas 
should be collected over mercury. The 
rationale of this experiment is very 
simple } the lime combines with muri¬ 
atic acid, and the ammonia is set free. 

370. Ammonia has a powerful 
affinity for water, which absorbs 
600 or 700 times ifs bulk of this 
gas. This solution of the gas in water is known as u aqua am¬ 
monia,” and u spirits of hartshorn.” It is the form under which 
ammonia is used in the operations of a laboratory. Aqua am¬ 
monia is obtained by passing a stream of the gas into distilled 
water. 

Experiment. The retort, containing muriate of ammonia and 
lime is subjected to heat; ammoniacal gas rises and is received in 
a vessel containing cold water, by which it is rapidly absorbed. 

Heat is evolved during the ab¬ 
sorption. The solution obtained is 
transparent and colorless, and has 
the odor and chemical properties 
of the gas itself. It is lighter than 
water, and its specific gravity is a 
test of its strength ; it being the 
lighter in proportion as it is strong¬ 
er. If 16ft open to the air, it grows 
weaker by the loss of gas, and ab¬ 
sorbs carbonic acid, so as at last to 
be converted into bi-carbonate of 
ammonia. It may be frozen by a 
temperature of about 40° F., in 
which case most of the gas is giv¬ 
en off, and the ice obtained resem¬ 
bles snow. Heat begins to expel 
the gas at 130° F., but the boiling 
point rises as the solution grows 
weaker. All the gas, however, 
cannot be expelled by heat; for at 
last the solution distills over un- 


Fig. 63. 


370. Aqua ammonia. How obtained? Properties of this solution. 
Experiment showing that ammonia is expelled from its solution by heat. 
Union of ammonia with aqua vapor. Effect of this gas upon ice. 














160 


INORGANIC CHEMISTRY. 


changed. A very common and convenient method of 
obtaining the gas is by heating the solution in a retort. 

Experiment. The retort a, contains liquid ammonia 
which being heated by the lamp &, ammoniacal gas rises, 
and as it is lighter than air, it rises and takes its place 
in the upper vessel. 

The affinity of ammoniacal gas for water may be further 
shown by letting a small quantity of it escape into moist 
air, where on account of its union with aqueous vapor 
it will cause a cloudy appearance. If a piece of ice be 
passed into ajar of this gas, it is liquefied by it immedi¬ 
ately ; and the gas disappears, being absorbed in the wa¬ 
ter produced by the melted ice. 

371. Smelling bottles are filled with some salt 
of ammonia mixed with a fixed alkali, to devbl- 
.ope the ammoniacal gas. The usual materials are 
carbonate of ammonia ; and carbonate of soda or potassa ; for the 
tendency of the fixed alkalies, to form fo-carbonates, enables 
their neutral carbonates to decompose carbonate of ammonia. 
The odor is improved by the addition of some fragrant oils or 
spices. The salts of ammonia are inodorous, except the carbon¬ 
ate. But they are easily detected by the action of heat, and by 
the development of the odor of ammonia on adding a fixed alkali. 
Free ammonia may be also detected by the white fumes formed 
on the approach of a rod dipped in muriatic acid ; and by its 
temporary action on moist turmeric paper, (see IT 368.) 

Nitrogen and hydrogen gases cannot be made to combine directly ; but 
in their nascent state, or at the instant in which they leave other combi¬ 
nations, they then unite, and form ammonia; this is always one of the 
products when animal matter undergoes decomposition, either spontane¬ 
ously or by means of heat. 

372. Hydrochlorate , or Muriate of Ammonia. This salt, com¬ 
monly called “ sal ammoniac ” is obtained by saturating muriatic 
acid with ammonia or its carbonate. Its chemical equivalent is 
63 ; it being constituted of 1 mu. acid 37 add 1 am. 17, add 1 
water 9=63. 


Fig. 64. 



371. Hartshorn smelling bottles. Tests for the salts of ammonia. In 
what state nitrogen and hydrogen unite. 

372. Composition and equivalent of muriate of ammonia. How ob¬ 
tained. Rationale of the change which takes place when sulphate of am¬ 
monia and nitrate of soda or magnesia are mixed. How are sulphate of 
ammonia and muriate of magnesia produced. 









AMMONIA. 


161 


Experiment. Into one retort «, 
put a small quantity of muriatic 
acid , and into another a, liquid 
ammonia: muriatic .acid, and am- 
monical gases will be evolved, 
and passing into the cylinder 

* unite and form dense white fumes, 

* which at length settle in solid 
concretions on the inner surface 
of the glass cylinder ; this pre¬ 
cipitate is muriate of ammonia. 

In the large way it is produced 
by mixing sulphate of ammonia 
and muriate of soda or magnesia in due proportions, and exposing the 
mixture to heat in a subliming apparatus. By double decomposition, 
muriate of ammonia and sulphate of soda or magnesia are formed ; the 
sal ammonia sublimes and is condensed in the cool part of the apparatus, 
while the sulphate remains fixed. The sulphate of ammonia for this 
purpose, is produced by lixiviating the soot of coal; and the muriate of 
magnesia is the principal solid ingredient in bittern , the uncrystallizable 
residue which remains after producing common salt by the evaporation 
of sea water. 

373. Muriate of ammonia dissolves in its weight of boiling water, or 
thrice its weight of water at 60“F. The boiling solution deposits crystals as 
it cools. The salt lias a pungent saline taste, is volatile below a red heat 

without decomposition, and condenses on cool 
Fi°\ 66. surfaces. It contracts dampness in a moist 

atmosphere, but does not deliquesce. It is 
anhydrous. It may be formed directly by 
mixing equal measures of ammoniacal and 
muriatic gases. 

Experiment. Let A and B, be two flasks 
with bent tubes containing the gases which, 
meeting in the bottle C, are condensed, and 
form muriate of ammonia. 

374. Nitrate of Ammonia is com¬ 
posed of 1 atom of nit. 1 of am. and 1 of 
water. It is readily formed by saturating nitric acid with 
carbonate of ammonia. The solution affords crystals by evapo¬ 
ration. If evaporated at 100° Fahrenheit, the crystals are large, 
striated prisms. If at 212° Fahrenheit, the crystals are fibrous. 
And at 300°, no regular crystallization takes place. The first 
variety contains 1 equivalent of the salt, and 1 of water ; the 
others contain less water. This salt in any form, is deliquescent. 
It dissolves in water so rapidly as to produce great cold, which 
is increased if ice or snow be substituted for water. Heat de¬ 
composes this salt at about 400° Fahrenheit. Water and protox- 

373. Properties of muriate of ammonia. How formed. Experi¬ 
ment. 

374. Composition of nitrate of ammonia. How formed. Crystals. 
Its deliquescence. Action of heat. Cause of explosion by heat. 






























162 


INORGANIC CHEMISTRY. 


ide of nitrogen are the products. Suddenly heated to 600°, it 
explodes violently, forming water, nitrous acid, deutoxide of ni¬ 
trogen, and nitrogen. The tendency which the elements of the 
acid and alkali have to form other compounds, and the volatile 
nature of those compounds, will account for the explosion. 

375. Chloride of Nitrogen. 4 Chi. 144 added to 1 Nit. 14=158. 
Chlorine does not combine with nitrogen, when both are in the 
gaseous state ; but if one of these gases is in the nascent state it will 
unite with the other, if present. Chloride of nitrogen is the most ex¬ 
plosive compound known, and is exceedingly dangerous. It is ex¬ 
ploded by a gentle heat, by slight friction, by agitation, and by the con¬ 
tact of many combustible substances ; as a rod dipped in olive oil produces 
detonation the instant of contact. The experiment should be made on a 
globule no larger than a mustard seed, which should be placed 
Fi 0, 67 at bottom °f a deep leaden vessel, the water will be dis- 
persed, and the vessel, perhaps, rent. The manner in 
Nv which this yellow oil-like fluid is transferred from one ves¬ 
sel to another, is by drawing it into a glass syringe having 
a pointed orifice, and a copper wire with a bit of tow wound 
closely round it for a piston ; thus a globule of very small 
size may be drawn into the tube, and deposited in the ves¬ 
sel prepared for the detonating experiment. The facility 
with which the decomposition takes place, is due to the 
small affinity of chlorine and nitrogen, and their strong ten¬ 
dency to resume the gaseous form; and the great violence 
of the explosion, is of course, the result of their immense 
expansion in passing from the liquid to the aeriform state. 
The products of the detonation, are chlorine and nitrogen 
gases. This experiment should never be made without 
strong gloves and glass masks. Its discoverer, Mr. Du- 
long, received a severe wound, in his first experiment with 
J J it; and Sir Humphrey Davy had his eyes seriously injured 
S/ in the same manner. 

376. Bromide of Nitrogen. This substance has simi¬ 
lar properties to the chloride of nitrogen, and may be formed in a similar 
manner. 

377. Iodide of Nitrogen. This is a black powder, and is obtained by 
pouring a solution of ammonia on iodine. It is very explosive ; but as 
one of the constituents is naturally a solid, the explosion is not quite so 
readily produced, nor so violent, as that of the chloride. It is resolved 
by the detonation into nitrogen gas and vapor of iodine. The iodide of 
nitrogen is supposed to consist of 3 equivalents of iodine=372 added to 
1 nitrogen 14=386. 


375. Composition and equivalent of chloride of nitrogen. In what 
state chlorine combines with nitrogen. Explosive nature of chloride of 
nitrogen Manner of transferring it. Cause of its ready decomposition. 
Violent explosion, and products of the detonation. 

376. Bromide of nitrogen analogous to the chloride. 

377. Properties and constitution of iodide of nitrogen. 









CARBON. 


163 


LECTURE. XVI. 


carbon.-compounds of carbon with oxygen and ammonia. 

CARBON. 6. 

378. Vegetable and animal bodies consist, essentially, of car¬ 
bon, oxygen, hydrogen and sometimes nitrogen. Many of them 
contain, also, several alkaline and earthy salts, and siliceous mat¬ 
ter, which are considered as accidental rather than necessary 
components. Growing vegetables derive their mineral substances 
from the soil in which they grow, and these are found more 
abundant in the bark where the circulating vessels are situated, 
than in the wood. When organic bodies are heated in the open 
air, the atmospheric oxygen combines with carbon, to form car¬ 
bonic acid; and with hydrogen to produce water ; and the pro¬ 
ducts of the combustion, being essentially gaseous, or very vola¬ 
tile, are dissipated, forming that very complex mixture of gases 
and vapors, called smoke. The alkaline and earthy salts, and 
siliceous matter not being either combustible or volatile, remain 
on the hearth , constituting ashes. 

But the results are quite different, when air is excluded. 
The organic matter is decomposed by the agency of heat, and 
most of its elements re-combine in various forms. The volatile 
products of this process, (called destructive distillation ,) are ex¬ 
ceedingly complicated. Among them, are impure vinegar, 
called Pyroligneous acid; an acid and fetid oil, to which the 
name empyreumatic oil has been given; carhuretted hydrogen 
or illuminating gas ; carbonic acid , ammonia , and watery vapor. 
The oxygen contained in these products, is that which belong¬ 
ed to the composition of the organic matter; and as this is 
never sufficient for the complete oxidation of the carbon and 
hydrogen, a large proportion of the former remains after the 
experiment. This, together with the ashes, constitutes char¬ 
coal. 


378. Essential constituents of vegetable and animal bodies. Accident¬ 
al components. M ineral substances most abundant in the bark of vege¬ 
tables. Products of the combustion of organic bodies when burnt in the 
open air. Different products when air is excluded. Volatile products 
of destructive distillation. Charcoal. 



164 


INORGANIC CHEMISTRY. 


379. There are several varieties of charcoal, of very different 
degrees of purity, but all deriving their common characteristics 
from the combustible element, carbon. 

Lamp-black is one of the purest of the common varieties. It is obtained 
by burning refuse oils and resinous matters in chambers hung with 
coarse matting. The smoke deposites free carbon, upon the matting, 
whence it is swept off and collected. 

Ivory-black , is an animal charcoal, and is obtained by heating bones 
excluded from air. It contains more earthy matter than vegetable char¬ 
coal, and is therefore more impure ; but is best for some purposes. The 
ashes it contains, are principally phosphate and carbonate of lime, which 
constituted the hardening matter of the bone. The ivory-black obtained 
in this manner, is that usually met with in commerce. The real ivory- 
black, is obtained from ivory. 

All the varieties of pit coal , or mineral coal, are carbon, more or less 
impure ; and are supposed to be derived from the spontaneous decompo¬ 
sition of vegetable matter. Some of them burn with flame, on account 
of their containing bituminous matter. Sulphur is a very frequent in¬ 
gredient ; and the matter of ashes abound in them. The ashes of mineral 
coal, however, differ from those of vegetable charcoal. The greater diffi¬ 
culty of igniting them, is chiefly owing to their greater compactness and 
density. One of the densest and purest varieties of mineral coal, is An¬ 
thracite , which contains more than 90 per cent, of carbon. Plumbago , 
or black lead, is carbon combined with a very small proportion of me¬ 
tallic iron. Its composition is variable. Coke , is a very dense and im¬ 
pure variety of carbon, obtained by the distillation of bituminous coal. 
The leading object of the distillation, is the furnishing of gas for illumina¬ 
tion, which is evolved in large quantity. Coke is the residual product. 
It is exceedingly difficult of combustion, but when burning in a blast fur¬ 
nace, gives an intense heat. Mixed with wood charcoal, it is largely 
used in smelting iron ores, and other metallurgic operations; and its im¬ 
portance is such, that coal is frequently distilled for the sake of the coke, 
though the gas be wasted. 

380. Nearly pure carbon may be obtained by passing the vapors 
of alcohol, ether, and the volalile oils, through porcelain tubes, 
heated red hot. 

The purest native variety of carbon, is the diamond, which is 
crystallized carbon. Many attempts have been made to make di¬ 
amonds, by fusing and by crystallizing carbon, but without suc¬ 
cess. It resists fusion, even in the intense heat of a powerful 
galvanic apparatus, and no menstruum has been found to deposit 
it in crystals. Yet there is abundant evidence of the identity of 
this gem with carbon. 

The diamond is the hardest body known. Its specific gravity 


379. Varieties of charcoal. Lamp-black. Ivory-black. Mineral coal 
its origin. Why some kinds burns with flame. Difference in the ashes* 
of mineral and vegetable charcoal. Anthracite. Plumbago. Coke. 

380. How may carbon be obtained nearly pure ? Crystallized carbon. 
Properties of the diamond. Experiment showing the combustion of a 
diamond in oxygen gas. Product of the combustion of diamond in oxy¬ 
gen gas. 




CARBON. 


165 


is a little above 3.5. It is generally colorless, but sometimes 
tinted. It has a highly crystaline structure, its primitive form 
is an octohedron. It is a most powerful refractor of light, to 
which, with the angular forms into which it is cut, it gives its 
brilliant play of colors, called its water. Newton conjectured the 
combustible nature of the diamond, on account of its great refrac¬ 
tory power, before any proof of this property had been obtained. 
It .may be consumed by an intense heat in the open air, or by 
heating it strongly with nitre. But the most brilliant mode of 
burning diamonds, is in an enclosed portion of oxygen gas, acted 
upon by a jet of hydrogen. 

Experiment. The figure repre¬ 
sents a glass globe, having fitted 
to its neck, a copper cap, with an 
apparatus into which a stop cock 
is screwed, and from which a jet- 
pipe, «, passes up into the globe. 
Above this pipe, are two wires, c c, 
one of which is attached to the jet- 
pipe, the other passes through an 
insulating glass tube, to the outside 
of the apparatus, where it termi¬ 
nates at a. At the end of the jet- 
pipe, is a small platinum grate. On 
this, the diamond is placed, and in 
such a situation, that the stream of 
hydrogen which issues from the 
jet, plays upon it, and not on the 
platinum. The lower part of the 
apparatus, has in its side, an aper¬ 
ture, to which is affixed a tube 
with a stop cock ; and with this 
is connected a bladder filled with 
hydrogen gas. When the apparatus is used, the glass globe is removed 
from its stand, placed on an air pump, exhausted of air, and then filled 
with oxygen gas; after which it is again screwed to the stand. The 
wire, <Z, is then connected with the conductor of an electrical machine by 
means of a chain wire ; a discharge of electrical sparks is then to pass 
between the wires c c. A stop cock being now opened, hydrogen gas 
being pressed from the bladder, issues through the jet-pipe a, and the 
diamond is heated to a white heat; after which, it takes fire and consumes. 
The product of this combustion is carbonic acid , which is the same as 
that arising from the combustion of pure charcoal. 

381. There are two modes of making wood charcoal. The most com¬ 
plete process is that used by manufacturers of gun powder, who require 
very pure charcoal. The process consists in distilling the wood in cylin¬ 
drical retorts of cast iron. The ordinary wood charcoal for fuel, is pre¬ 
pared by covering a pile of wood with earth, so as nearly to. exclude air, 
and then set it on fire at the bottom. This is a very imperfect process. 


381. Modes of preparing wood charcoal. The kinds of wood best for 
charcoal. 


Fig. 68. 



15 









166 


INORGANIC CHEMISTRY. 


The air not being quite excluded, a considerable portion of carbon is 
consumed, and the quality of the remainder is impaired. The product is 
said to be greatly increased, when the interstices of the pile are filled 
with the refuse coal dust of a former burning. The wood of young 
trees is better than old, not only as affording a larger product for the 
same weight of wood, but as giving coal of a purer and better quality. 
Branches are better than the main trunk of the tree. The principal 
portion of the ashes comes from, the bark, which ought to be stripped off. 
Dead and sapless woods, afford a less pure coal, than wood which is cut 
W’hen the sap is in full circulation. For the manufacture of gun-pow¬ 
der, the lighter woods, as willow, elder, poplar, dog-wood, &c., afford 
the best coal. The bark is stripped off, and the pith removed, the pieces 
being split to a diameter of 3-4 of an inch. 

382. Carbon is black, brittle, pulverulent, unaltered by the 
action of air and moisture at common temperatures, and not af¬ 
fected by heat, even the most intense, when air is excluded. It 
is neither volatile nor fusible, is insoluble in all menstrua ; is not 
attacked by alkalies, nor, at Common temperatures, by any acid. 
Its specific gravity is said to be greater than that of diamond; 
wood charcoal, on account of its porosity* floats awhile on water, 
but sinks as soon as its pores are filled with the fluid. Charcoal 
is an excellent conductor of electricity, but a very bad conductor 
of heat', especially when powdered. 

Charcoal has a remarkable antispeptic power, preventing the 
putrefaction of meat and vegetables which are covered with its 
powder. For this reason it is customary to char the end of 
post and piles that are to be set in the earth ; the inside of the 
water casks of ships, are often charred for the same reason. 
This property also renders finely powdered charcoal an excellent 
dentrifice, especially as the extreme hardness of its particles 
gives it a great polishing power j on account of the last circum¬ 
stance, this powder should not be used too frequently, as it 
wears the teeth. Charcoal is very effective in removing color¬ 
ing matter from liquids of vegetable origin. Dark colored vine¬ 
gar is rendered colorless as water by filtration through powdered 
charcoal. This property is lost, after several repetitions, but 
is restored by heating the charcoal to redness. The decolor¬ 
ing power is greater in animal, than in vegetable charcoal, on 
account of the greater quantity of earthy salts contained in the 
former. 

383. Charcoal absorbs the odoiiferous principles of vegetables. 
Tainted meat becomes sweet after being sometime covered with 

382. Properties of carbon. Antispeptic property. Valuable as a den¬ 
trifice. Effect in the decolonization of liquids. 

383. Absorbing property. Its use in restoring tainted meat,&c. On what 
the absorbing power depends. What gases most readily absorbed. De¬ 
grees of absorption of different gases by charcoal. 



CARBONIC ACID. 


167 


it; and by filtration through its powder, putrid water is rendered 
pure. Charcoal absorbs gases and vapors. This is a mechani¬ 
cal effect, depending on the porosity of the charcoal. Of the dif¬ 
ferent gases, it absorbs different quantities, dependent on the rel¬ 
ative elasticity of the gases ; the least elastic, and therefore most 
easily condensible gases, are absorbed in the greatest quantities. 
Vapors are, therefore, more absorbable by charcoal, than gases, 
and liquids, still more than vapors. 

Fresh charcoal from box-wood, according to Sassure’s experiments, 
absorbed in 24 or 36 hours, 


of Ammoniacal gas, 

90 times its bulk. 

“ Sulphurous acid 

gas, 

65 

44 

“ Carbonic acid 

44 

35 

44 

“ Oxygen 

(t 

9.42 

44 

“ Nitrogen 

u 

7.05 

44 

“ Hydrogen 

44 

1.75 

44 


384. Charcoal burns when heated to redness in air or in ox¬ 
ygen gas. In the former, the combustion is slow, in the latter, 
brilliant, with emission of sparks. In either case, and in all 
other examples of the direct oxidation of carbon, the product 
is carbonic acid gas. If pure, the charcoal is consumed without 
residue. Charcoal is also oxidized by being heated with nitric 
acid ; but the nitrates, chlorates, and other deflagrating salts, 
yield their oxygen to it very rapidly at a red heat, causing the 
violent combustion, called deflagration. Metallic oxides, also, 
by the aid of more or less heat, are reduced by charcoal to the 
metallic state, upon which property are founded most of the pro¬ 
cesses for obtaining metals from their ores. There are many 
other processes, both in Chemistry and in the arts, in which 
charcoal is employed as a powerful deoxidizing agent. 

COMPOUNDS OF CARBON AND OXYGEN. 

385. Carbonic Acid Gas. 1 Car. 6 add 2 ox. 16 = 22. 

This gas is constantly found in the atmosphere, being gene¬ 
rated by combustion, respiration, and many other processes. It 
is contained also in many solid mineral bodies ; thus chalk, mar¬ 
ble, Iceland spar, and limestone, all consist of the same compound 
of carbonic acid and lime, in different degrees of purity. This is 


384. Combustion of charcoal. Product of the combustion. Action of 
charcoal when heated with nitric acid, or with deflagrating salts. Re¬ 
duction of metallic oxides by charcoal aided by heat. 

385. Composition of carbonic acid gas. Where found ? Importance 
of its discovery. Observations of Van Helmont and Hales. Discovery 
of Dr. Black. Priestley and Lavoisier. 



168 


INORGANIC CHEMISTRY. 


the first gas that was distinguished from common air; its discovery 
opened a new field of investigation, that of the elastic fluids,which, 
since 1775, has changed the aspect of the science. 

The first steps towards this discovery, may be traced to the Alchemist 
Van Helmont, who observed that calcareous stones sometimes yielded an 
air , to which he gave the name of gas. Hales afterwards asserted, that 
this sort of air was an essential part of these stones; and he attempted 
to ascertain in what proportion it existed in them. Dr. Black soon after 
discovered that this air was capable of being absorbed by lime and the 
alkalies, of neutralizing them, and causing them to effervesce with acids. 
Priestley studied its properties with much care, and the English Chemists 
usually ascribe to him the honor of its discovery. But the French as 
sert that their countryman Lavoisier first determined the proportion of 
its constituent parts, and understood its nature. It appears that both 
Priestley and Lavoisier were at the same time engaged in studying and ex¬ 
perimenting upon this gas, and publishing in their respective countries 
the results of their investigations. 

386. Carbonic acid gas was at first named fixed air , on ac¬ 
count of its remaining in a fixed state in stones and rocks; it 
has been called aerial acid , chalky acid and gaseous oxide of carbon. 
It received its present name on the reformation of the chemical 
nomenclature. 

387. Carbonic acid may be obtained by burning pure charcoal 
in oxygen gas, or by exposing almost any of its numerous and 
abundant combinations with the metallic oxides to a strong red 
heat, in an iron retort. 

But the easiest method of obtaining it is to pour one of the stronger 
acids, (as the muriatic) in a dilute state, upon small fragments of mar¬ 
ble or other carbonate, in a flask or stopped glass retort. The muriatic 
acid unites with the lime of the marble, forming muriate of lime, and 
displacing the carbonic acid. The gas may be collected over mercury, 
or over water in the usual manner ; or, as it is much heavier than air, it 
may be received in a dry glass bottle or jar, standing with its mouth up¬ 
wards ; in this case, the tube proceeding from the flask must be bent 
twice at right angles, and reach quite to the bottom of the receiving ves¬ 
sel. 


386. Different names of carbonic acid gas. 

387. Modes of obtaining carbonic acid gas. Experiment showing a 
mode of obtaining this gas. 




CARBONIC ACID. 


169 


Experiment. Thus, into the double necked 
bottle, here represented, put fragments of mar¬ 
ble, and pour through the funnel diluted mu¬ 
riatic acid; effervescence immediately ensues, 
and the disengaged carbonic acid gas, filling 
the bottle, passes out through the bent tube a, 
into the jar b ; and on account of its being 
heavier, crowding out the atmospheric air 
which the jar contained. When the jar is full, 
a lighted taper will be extinguished, if held 
just within its mouth. 

388. This gas is transparent, colorless, 
tasteless, inodorous, and highly elastic; 
Its specific gravity is above 1.5 ; it extin¬ 
guishes burning bodies, and destroys the 
life of animals immersed in it; and these effects are not due to 
the mere absence of oxygen, for they take place even when some 
peroxygen is present. Thus charcoal, wood, candles, and 
other carbonaceous substances, are extinguished before the oxy¬ 
gen is consumed, by reason of the mixture of the latter with the 
carbonic acid which is produced in the combustion. And hence 
persons are often suffocated by pans of burning charcoal in apart¬ 
ments not sufficiently ventilated. The unwholsome effect of 
crowded assemblies, is partly due to the carbonic acid produced 
by respiration. This gas acts on the system as a narcotic poison. 

It is often found in wells, pits, and caverns, being generated 
there by the spontaneous decomposition of organic matter, or of 
earthy carbonates. Before descending into such places, it is 
proper to let down a burning candle. If it be extinguished, the 
air there is unfit to support respiration. Another test is clear 
lime water , which becomes covered with a pellicle of carbonate of 
lime when exposed to an atmosphere of this gas. It may be re¬ 
moved in such cases, by letting down buckets containing a mix¬ 
ture of lime and water, as the lime unites with the carbonic acid 
gas to form carbonate of lime ; or it maybe drawn up in buckets, 
and poured out like water. 

388. Properties of carbonic acid gas. Its effects on combustion and an¬ 
imal life. Pans of burning charcoal in close rooms. Air of crowded as¬ 
semblies. Air of wells, pits, &c. Tests by which the presence of car¬ 
bonic acid gas may be known. How may the gas be removed ? 

15* 


Fig. 69. 













170 


INORGANIC CHEMISTRY. 


Fig. 70. 



389. Put intd a three necked 
bottle, two ounces of the car¬ 
bonate of ammonia, and one 
ounce of orange colored ni¬ 
trous acid, carbonic acid gas 
will be evolved and be visible 
as it rises in a cylindrical jar, 
fitted to the bottle. When full, 
it will press out beneath the 
cover at the top of the jar. 
Let the cover be removed, 
and a candle introduced with¬ 
in the vessel, and it will be 
extinguished. The gas can 
be drawn off at A ; its current 
will be visible, and it will ex¬ 
tinguish a burning candle 
held beneath the orifice. It 
can be drawn like a liquid, in¬ 
to a tumbler, from whence it 
may be poured upon a burn¬ 
ing lamp which it will extin¬ 
guish. 

Fig. 71. 



390. As water absorbs carbonic acid gas, another mode of re¬ 
moving it from wells, &c., is to pour down a quantity of w r ater. 
Animation, when suspended by the effect of this gas, has been 
restored, in some cases, by dashing cold water over the patient. 

Water absords its own bulk of carbonic acid gas, at the ordi¬ 
nary temperature and pressure of the atmosphere ; under a great¬ 
er pressure, a larger quantity is absorbed. Thus a pressure of 
two atmospheres causes water to absorb twice its bulk of the 
gas ; three atmospheres, three times its volume, and so on. By 


389. Experiment to shew that carbonic acid gas is heavier than atmos¬ 
pheric air. 

380. Absorption of carbonic acid gas by water. Effect of pressure on 
this absorption. Soda or carbonated water. Describe Dr. Hare’s appa¬ 
ratus for carbonating water. What takes place when the water is re¬ 
lieved from pressure ? 


















CARBONIC ACID. 


171 


a pressure equal to thirty six atmospheres, carbonic acid itself 
becomes a liquid. 

By compressing carbonic acid gas over water with a forcing 
pump, the water becomes highly charged with the gas, and form- 
what is sold as soda water , but in general, is merely carbonated 
water . 


Dr. Hare's apparatus for charging water with carbonic acid. 


Fig. 72. 



A, is a condenser fastened into a block of brass furnished with a coni¬ 
cal brass screw, by means of which, it is easily attached to the floor. In 
this block are two valves, one opening inwardly from the pipe B, the 
other outwardly towards the pipe C. The pipe B, communicates with a 
reservoir of gas which the condenser draws in, and forces-through the 
other pipe, into a strong copper vessel containing the water. The car¬ 
bonated water is drawn out by means of a syphon D. When the pres¬ 
sure on the water is relieved, the greater part of the gas escapes with 
effervescence, leaving only what the water is capable of holding in so¬ 
lution, at ordinary atmospheric pressure. The remainder may be ex¬ 
pelled by boiling the water or by placing it under the receiver of an air 
pump, and exhausting the air. 

391. Water which contains carbonic acid gas, has a lively, 


391. Properties of carbonated water. Tests of carbonic acid in water. 
Cause of the crust which is deposited when spring water is boiled. 




































172 


INORGANIC CHEMISTRY. 


brisk taste, sparkles when poured from one vessel to another, and 
changes to red the blue color of litmus paper ; but the latter ef¬ 
fect is only temporary, for the acid soon evaporates and the blue 
is restored. The insipid taste of boiled water is owing to its 
having lost the carbonic acid which spring waters always contain. 
The presence of this gas in water, may be detected by mixing 
it with clear lime, or baryta water ; it becomes milky, on 
account of the formation of an insoluble carbonate of lime or 
baryta. But care should be taken to have the alkaline water 
in excess ; for if the carbonated water predominate, the precip¬ 
itate is not formed, or is re-dissolved, those carbonates being 
soluble in excess of carbonic acid. On account of the latter 
property, the spring waters of a limestone district, often contain 
carbonate of lime in solution. On boiling, the excess of car¬ 
bonic acid is expelled, the carbonate of lime is deposited, and by 
frequent repetition, the vessel in which it is boiled, becomes lined 
with a white calcareous crust. 

392. Carbonic acid gas is a product of fermentation. If cider, 
beer, champagne, &c., be put into bottles, and tightly corked 
before the fermentation has entirely ceased, the gas which is gen¬ 
erated during the remainder of the fermentation, is forced into 
the liquids under a considerable pressure, and gives them the ef¬ 
fervescent quality or liveliness, which renders them agreeable. 
An overcharge of the gas, expels the cork or bursts the bottle ; 
and this will happen when the liquors are bottled too soon. 
This occurrence often takes place in bottled yeast, which, in fer¬ 
mentation, gives off a large proportion of gas. 

393. It has been remarked, (§ 349j) that carbonic acid gas is 
always present in the atmosphere, and that the vegetation of 
plants has an agency in decomposing it and restoring oxygen to 
the air. A small proportion of carbonic acid in the atmosphere 
is favorable to vegetation, by furnishing carbon to the plants ; but 
in too large proportion, it destroys vegetable life. It has been 
found that plants are benefited by being watered with a solution 
of this gas. Carbonic acid combines with the alkalies, earths, 
and most of the salifiable metallic oxides, forming a class of salts 
called carbonates , many of which occur abundantly as minerals, 
as carbonate of lime in its various forms of limestone, chalk, 
marble, Iceland spar, Stalactite, &c. The carbonic is a very 
weak acid, and does not completly neutralize the alkalies ; there¬ 
fore all the carbonates are decomposed by muriatic, nitric and most 

392. Cause of the effervescence and other peculiar properties of fer¬ 
mented liquors. Bursting of the bottles containing such liquors. 

393. Decomposition of carbonic acid gas by "plants. " Carbonates. 
Why easily decomposed ? 



CARBONIC OXIDE. 


173 


other acids, carbonic acid escaping with effervescence. All the 
carbonates, except those of ammonia, potassa, soda and lithia are 
decomposed by heat. 

394. Carbonic acid is the highest known oxide of carbon. It 
contains in bulk one volume of carbonic vapor and one volume 
of oxygen, condensed into one volume : or by weight, it consists 
of 1 car. =6 add 2 ox. = 16=22. 

Its composition is proved by passing the vapor of phosphorus over a 
red hot carbonate, in which case phosphoric acid is formed and carbon 
set free ; or by passing a succession of electric sparks through the gas, 
by which means it is resolved into oxygen and carbonic oxide ; or by 
electrifying a mixture of hydrogen and carbonic acid when water and 
carbonic oxide will be formed. It is also decomposed by being brought 
in contact with iron filings or charcoal at a red heat; the iron or char¬ 
coal takes half its oxygen, converting it into a carbonic oxide. Potas¬ 
sium takes the whole of its oxygen ; forming potassa and liberating car 
bon. 

395. Carbonic acid gas has been liquefied by very powerful compres¬ 
sion aided by exposure to cold. Mr. Faraday obtained it in this state by 
disengaging it from carbonate of ammonia by means of sulphuric acid, 
in a glass tube hermetically sealed, one end being immersed in a freezing 
mixture. The liquid acid was colorless, and floated upon the sulphuric 
acid and water, contained in the tube. The pressure under which this 
fluid was formed was estimated to be equal to that of thirty six atmos¬ 
pheres. A French Chemist* who had previously succeeded in liquefy¬ 
ing this gas, announces that he has also obtained it in a solid state. Its 
solidification requires a cold equal to 100th degree of the centigrade be¬ 
low the freezing point; and, though the liquefied gas evaporates almost 
instantaneously, and with a violent explosion, the solid continues some 
minutes exposed in the open air, and insensibly disappears by a slow 
evaporation. The first instance of a gas becoming solid and concrete is 
so much-the more remarkable as it relates to a gas, to liquefy which re¬ 
quires the most powerful mechanical action, and which resumes with 
great rapidity its gaseous state when the compression is removed. In 
the liquid state its elastic force is equal to that of gun-powder, while in 
the solid state the spring appears Completely broken, the new body dis¬ 
appearing by slow evaporation. 

396. Carbonic Oxide Gas. This is the compound of oxygen 
and carbon in which the former element is in the lowest propor¬ 
tion. Its constituents are, 1 atom of carbon with 1 of oxygen. 
It is never formed by the direct oxidation of carbon, carbonic 
acid being always the product. Most of the processes for ob- 

• * M.Thilorier. See Silliman’s Journal, Oct. 1836 ; and also the same 
Journal for Jan. 1837. Translations from Annales de Chimie. 


394. Composition of this gas. How proved. 

395. Pressure under which it was formed. Solidification of carbonic 
acid. 

396. Composition of carbonic acid gas. How formed. How obtain¬ 
ed by heating chalk with iron filings ? How obtained by means of oxa¬ 
lic and sulphuric acid. Dr. Hare’s apparatus for separating carbonic 
acid gas from carbonic oxide. 



174 


INORGANIC CHEMISTRY. 


taining carbonic oxide depend on depriving carbonic acid of 
half its oxygen ; this is easily effected at a red heat by charcoal 
and by several of the metals. Thus when a mixture of chalk 
and iron filings are heated to a red heat, carbonic acid is driven 
from the chalk; the hot iron immediately takes a part of the 
oxygen from the carbonic acid and reduces it to carbonic ox¬ 
ide. When charcoal is used for this purpose, it is itself con¬ 
verted into carbonic oxide. The gas thus evolved may be col¬ 
lected over water. 

Other more easy and elegant processes are founded on the decomposi¬ 
tion of oxalic acid and its salts by sulphuric acid. Oxalic acid is a crys- 
talizable, poisonous, vegetable acid, which like nitric acid is incapable of 
existing in an uncombined state; so that when not united to a salifiable 
base it always contains water. Besides this water necessary to its exist¬ 
ence, the crystalized acid consists of 3 atoms of oxygen and two of car¬ 
bon. On heating this acid or its salts in a glass retort, with an excess of 
sulphuric acid, the latter takes both water and alkaline base ^ the oxalic 
acid, thus set free, resolves itself into the two gaseous compounds of car¬ 
bon and oxygen. These mixed gases being collected over mercury, the 
carbonic acid will be speedily absorbed by a little milk of lime or solu¬ 
tion of. potassa, and the carbonic acid remain pure. 

The gases being obtained in the manner directed above, they are con¬ 
veyed by means of the pipe P, (which is supposed to communicate with 
a reservoir of the mixed gases,) to the bell glass C, containing lime wa¬ 
ter. The lime water sinks into the lower bell glass, A, as the gases are 
introduced by turning the stopcock communicating with the pipe P. The 
lower pipe D, communicating with the bell glass A, has affixed to it an 
india rubber bag ; by pressing this with the hand, jets of lime water are 
thrown into the gas in the bell glass C, until all the carbonic acid having 
united with the lime, the carbonic oxide is left pure, and may now be 
transferred to any receiver by turning the stop cock of the pipe. P. 

397. Carbonic oxide is transparent, colorless and inodorous ; 
it is very sparingly absorbed by water ; its specific gravity is 
0.972. It has neither acid nor alkaline properties, and has no 
effect on lime w r ater. It extinguishes burning bodies, and is ir- 
respirable, being like carbonic acid, a narcotic poison. It is in¬ 
flammable, burning in contact with oxygen with a pale flame. 
In this, and all cases of its direct oxidation, carbonic acid is the 
sole product. 

Experiment. Place an inverted jar over a vessel of carbonic , 
oxide which is burning in a jet, as it issues from the tube at the 
mouth. The inverted jar will be filled with carbonic acid gas. 
The air furnishes another atom . of oxygen=8, which uniting 
with the carbonic oxide=14 makes carbonic acid=22. 


397. Properties of carbonic oxide. Experiment. To prove that car¬ 
bonic oxide is combustible, and that the result of its combustion in the 
air is carbonic acid gas. Blue flame of carbonic oxide seen in coal fires. 



CARBONIC OXIDE. 


175 


Dr. Hare's apparatus for purifying carbonic oxide by lime water. 


Fig. 73. 



The blue flame of carbonic oxide is sometimes seen on the up¬ 
per part of a charcoal or anthracite fire; the draught of air en¬ 
tering below, the combustion of the coal there produces carbon¬ 
ic acid, which, in rising through the mass of ignited coal, is de¬ 
composed and converted into carbonic acid- 

398. Carbonic oxide gas being mixed with half its volume of 
oxygen gas, the mixture may be exploded by an ignited body or 
by the electric spark, carbonic acid being the product. It may 

398. Explosive mixtures with carbonic oxide. Constitution by weight 
and volume. 












176 


INORGANIC CHEMISTRY. 


also be exploded in a similar manner by mixing it with protox¬ 
ide of nitrogen. 

Carbonic oxide consists, by weight, of one equivalent of car¬ 
bon 6=and one of oxygen=8, its proportional number is there¬ 
fore 14. By volume, its constituents are one measure of carbon 
vapor, and half a measure of oxygen gas, condensed into ope 
measure. 

Carbonic acid with Ammonia , or Carbonates of Ammonia . 

399. The neutral carbonate of ammonia is a dry white powder, having 
the odor of ammonia, though not in so high degree, and very soluble in 
water. It is never met with in commerce, and can only be formed by 
mixing one volume of carbonic acid gas, and two of ammoniacal gas, 
both in a perfectly dry state , over mercury. Both gases disappear entire¬ 
ly, and the white powder of carbonate of ammonia is deposited. 

400. The Sesqui * carbonate is the commercial carbonate of ammonia. 
It is procured in an imppre state for the purpose of forming muriate of 
ammonia, by heating bones and other animal matter in close vessels. 
Animal matter being composed of carbon, oxygen, hydrogen, and nitro¬ 
gen, the elements are separated by the agency of heat and recombined 
in other forms, one of which is the salt in question. The sesqui-carbon- 
ate of the shops, is procured by sublimation from a mixture of muriate 
of ammonia with carbonate of lime. On exposure to the air this salt 
becomes opake and pulverulent, loses its odor and decreases in weight. 
It is then found to have become bi-carbonate of ammonia. Bi-carbonate 
of ammonia is formed as above, by exposing the sesquicarbonate to the 
air. It is also obtained by passing a current of carbonic acid gas through 
a solution of the common carbonate. On evaporating the solution, the 
salt crystalizes. 


LECTURE XVII. 

Compounds of Carbon with Hydrogen. 

401. Carbon and hydrogen possess opposite properties in re¬ 
spect to their tendency to assume the gaseous form. They have 
a strong affinity for each other, and their compounds are remark¬ 
able for their inflammable nature. Carbon and Hydrogen form 
at least, six definite compounds ? 

* Latin term, signifying one and a half. 


399. Neutral carbonate of ammonia. 

400. Sesqui carbonate of ammonia. How prepared. Its properties. 
How is the bi-carbonate of ammonia formed P 

401. Affinity of carbon and hydrogen for each other. Different forms 
under which they combine. Names and composition of these com¬ 
pounds. States in which they exist. 




CARBURETTED HYDROGEN. 


177 


1. Light carburetted hydrogen gas, 

consisting of 

2. Olefiant gas, « 

3. Faraday’s bicar. hyd. “ 

4. “ Quadrocarburet, “ 

5. Naptha, “ 

6. Napthaline, “ 


1 equivalent add 

to 2. i 

eq, 

2 

u 

it 

2. 

tt 

6 

it 

it 

3. 

tt 

4 

tt 

it 

4. 

it 

6 

it 

it 

6. 

tt 

3 

it 

it 

2. 

tt 


Of these, the first two are permanent gases. The fourth is 
a vapor at common temperatures, but a liquid at 0^ F. the third 
and fifth are volatile liquids ; and the last is a volatile solid. 

402. It is to be observed that several of these compounds present a 
remarkable exception to the laws of combination. The second, fourth 
and fifth consist of carbon and hydrogen in precisely the same ratio , 
that is, one equivalent of each element; yet they are totally distinct in 
all their physical, and most of their chemical properties; nor have we 
any right to suppose that a compound consisting of one proportional of 
hydrogen and one of carbon would resemble either of them. The con¬ 
stitution of these bodies seems to indicate that, for the formation of any 
specified compound, not only must certain proportions be observed in the 
quantities of the constituents, but also, that the concurrence of a par¬ 
ticular number of atoms is necessary. Thus, if we could compel three 
atoms of olefiant gas to cohere, we should probably obtain an atom of 
Naptha ; and if two atoms of the same gas were to coalesce, they might 
form an atom of quadrocarburet. The analysis of some organic bodies 
proves that slight variations in composition or different modes of combi¬ 
nation may produce great differences in properties : there is but one 
other case, that of hydrophosphoric acid, in which the laws of combina¬ 
tion appear so inexplicable as in the present. Until more light is thrown 
upon the subject, we must be content to attribute the difference of prop¬ 
erties, among bodies containing the same elements in the same proportions, 
to the influence of the mode of combination .* 

403. Light Carburetted Hydrogen. This gas is also called 
sub-carburretted hydrogen gas , and bi-hydroguret of carbon. It is 


* Since these anomalies in the laws of chemical combinations began 
to attract the attention of men of science ; they have been arranged 
under different heads ; as Isomerism , from the Greek isos equal, and 
meros a part; polymerism from polus many and meros; and metamerism , 
according to, and meros. Isomeric bodies are those which contain the 
same absolute and relative number of atoms of the same elements, and 
have, therefore, the same atomic weight; Polymeric bodies are those 
which contain the same relative, but not the same absolute number of 
atoms of the same elements, and whose atomic weights are consequent¬ 
ly unlike. Metameric bodies are those which, while they contain the 
same absolute, and the same relative number of atoms of the same ele¬ 
ments, yet constitute substances belonging to an entirely different class 
of bodies, or a different order of chemical compound. The carburets 
are therefore polymeric bodies. 

(Rep. of the British association for 1835 p p. 435, 436.) 

402. Exception of some of these compounds to the laws of combina¬ 
tion. 

403. Synonymes of light carburetted hydrogen. How formed, and 
obtained ? Natural reservoirs of this gas. 

16 



178 


INORGANIC CHEMISTRY. 


also known as inflammable air, and the air of marshes. It can only 
be obtained, in a separate state, by stirring the mud of stagnant 
pools, and collecting the bubbles of gas as they arise in an invert¬ 
ed receiver filled with water. It is formed in such situations 
during the spontaneous decomposition of vegetable matter. 

There is a rivulet running through the village of Fredonia, and 
another which passes by Portland Harbor, both in Chautaugue 
County in the State of New York, from the waters of which 
bubbles of light carburetted hydrogen gas are constantly rising. 
The supply of gas at Fredonia is sufficient for lighting the houses 
of the village, and a gasometer has been constructed for collecting 
it. The light house on Lake Erie at Portland harbor is com¬ 
pletely supplied with gas obtained from the rivulet above men¬ 
tioned. The orgin of the gas in these cases has not been traced. 

404. This gas is colorless, transparent, tastless, inodorous, 
sparingly absorbed by water, and of specific gravity 0.5555. It 
burns with a yellow flame ; and if mixed with air or oxygen in 
proper proportions, it explodes violently, when touched with 
flame or the electric spark. Whether exploded, or burnt silent¬ 
ly, the sole products are carbonic acid and water. 

405. Light carburetted hydrogen is often generated in large 
quantities in coal. Sometimes it is pent up in cavities where it 
was formed, and, being under great pressure, rushes out with 
much force, when a cavity is broken into; a reservoir of this 
description, is called by the miners, u a blower.” At other times, 
it issues silently from between the layers of coal. In either case, 
it mixes with the air of the mine, constituting the fire damp of 
the miners, and if set on fire, explode, with terrible violence, 
producing a shock which has sometimes been felt at a distance 
of several miles. By the explosion of the fire damp , carbonic 
acid and water are produced ; so that if it were possible for a 
miner to escape the effect of concussion, he would perish by 
suffocation in the mephitic gas, which the miners call choak damp . 
Such explosions were frequent in the British coal mines, till a 
few years ago ; and the annual loss of life occasioned by them, 
was truly deplorable. It was reserved for the genius of Davy, 
to discover a remedy for this great evil; a task to which he 
brought great ingenuity in devising experiments, and industry in 
executing them ;—a close observation of facts, and an acuteness 


404. Properties. Products of its combustion. 

405. Blowers of mines. Fire damp, its properties, &c. Choak damp. 
Davy’s safety lamp. Observations on flame which lead to Davy’s in¬ 
vention. Different temperatures of different flames. Gases kindled by 
solid bodies at different temperatures. Explosive mixture of light car¬ 
buretted hydrogen and oxygen. 



CARBURETTED HYDROGEN. 


179 


in reasoning, which conducted him to the most complete success. 
By means of this little instrument, whose simplicity is scarcely 
less admirable than its utility, thousands of lives have already 
been saved. The miner now fearlessly descends into dark cav¬ 
erns filled with combustible gases, and lamp in hand safely pur¬ 
sues his daily avocations, undisturbed by the terror of destructive 
explosions. 

In the course of his experiments, Sir H. Davy developed some facts 
which go to illustrate the nature of flame, a subject which had not pre¬ 
viously been much investigated. 

Flame he found to be gaseous matter in a state of incandescence, and 
its temperature far higher than any to which solid bodies can be brought. 
This being the case, in order to extinguish flame it is only necessary to 
cool it; this may be effected by bringing it into contact with a sufficient 
quantity of solid matter which may convey away the heat by means of 
its conducting power. It would follow from this, that the greater the 
conducting power, the less the mass of solid matter necessary to effect 
the object, and vice versa; and consequently that metals would produce 
the effect more readily than any other bodies, the masses being the same. 
Some of these facts may be readily proved by simple experiments. If 
the point of a knife, or the end of a metallic wire be held very near to 
the flame of a candle, a dark spot will appear on the blaze opposite to tfie 
metallic point; the gas in that part being cooled below incandescence by 
the conducting body. If a very small flame be made with a cotton 
thread, passed through a cork shaving, and floating on oil, it will be ex¬ 
tinguished by holding over it, and in contact with it, an exceedingly 
small ring of fine iron wire ; a ring of glass of the same size, will di¬ 
minish the flame, and a larger glass ring will put it out, the sufficiency 
of conducting power being compensated by the greater quantity of matter. 

Davy found that flame would be extinguished in passing through nar¬ 
row tubes ; and that the diameter might be increased without impairing 
the effect, provided a material of greater conducting power were used ; 
also that the length might be diminished, provided the diameter were 
diminished proportionally. Now if a fine wire gauze be held upon a 
common flame, the flame will not pass through the gauze, but will ap¬ 
pear as if cut off, (See fig. 74 ,) on applying a lighted paper above the 
wire gauze, a flame will be produced on the upper surface, which is a 
continuation of the flame below. (See fig. 75,) The gas of which the 
flame consists, actually passes through the gauze, but is extinguished in 
its passage, by the cooling power of the wire. 





180 


INORGANIC CHEMISTRY. 



Fig. 76. 

Davy's Safety Lamp. A is a cylinder or case of wire 
gauze, having no less than 625 apertures to the square 
inch, with a double top securely fastened to the brass rim 
B, which screws on to the lamp C. The whole is pro¬ 
tected and rendered convenient for use, by the frame and 
ring D. 

In gas manufactories, spirit ware-houses, and in all 
places where inflammable vapors or gases are likely to be 
generated, as in the examination of foul sewers and 
drains, where artificial light -is required, it is obvious 
that these lamps have very important uses, as well as in 
the lighting of mines. 

As different flames have different temperatures, it will 
obviously be necessary to vary the texture of the gauze, 
according to the nature of the gas to be extinguished. 
Moreover it is necessary to observe, that some gases, as 
carbonic oxide, are kindled by a solid body at a dull red 
heat; others require a bright red, or a white heat, to set 
them on fire; while some are not ignited without the 
direct application of flame. It happens, that light car¬ 
buretted hydrogen requires a higher temperature for ig¬ 
nition than any other gas; this is fortunate, because the 
wire gauze must, necessarily become heated, which 
would cause the ignition of explosive mixtures, contain¬ 
ing other inflammable gases and vapor. 

406. Explosive mixtures, may be made to undergo a sort of slow com¬ 
bustion at a temperature below that of flame, and consequently without 
explosion. This fact may be demonstrated by immersing a small slip of 
platinum foil or wire, heated red hot, into a mixture of light carburetted 
hydrogen and air. The temperature of the heated metal will cause the 
oxygen to combine with carbon and hydrogen, enough heat being evolved 
by the chemical action, to keep the wire ignited, but not enough to set 
the gaseous mixture on fire. 

Upon this fact has been founded th e flameless lamp. 
A spiral coil of fine platinum wire is placed verti¬ 
cally, so as to surround the cotton wick and rise a 
quarter of an inch above it. Some alcohol being put 
into the lamp, the wick burns and ignites the platin¬ 
um wire. In this condition, if placed in an explo¬ 
sive mixture, and the wick be extinguished, the wire 
will continue to glow, giving light enough to guide 
the steps in darkness. 

407. It appears that an explosive mixture of any 
combustible gas with oxygen, is necessary to the 
production of flame, and that an ordinary flame is a 
mere shell, the interior of which is filled up with 
gas, which is not ignited. This fact may be demon¬ 
strated by a few simple experiments. 

Experiment lsi. Hold a thin glass tube, 6, about 

406. Slow combustion of explosive mixtures without flame. Heated 
platinum immersed in a mixture of light carburetted hydrogen and air. 

407. Experiments showing that flame is a shell, the interior of which 
contains gas not ignited. 









CARBURETTED HYDROGEN. 


181 


the diameter of a small quill, and three or four 
inches long, so that its lower extremity shall be 
immersed in the flame «, of a large candle, the 
tube making an angle of about 45 3 with the axis 
of the flame ; a portion of the gas J, from the in¬ 
terior of the flame, will pass along the tube, and 
may be set on fire at its extremity. 

Experiment 2nd. With a fine pointed glass syr¬ 
inge, gas may be drawn from the interior of a com¬ 
mon lamp flame, and on being gently pressed out, 
in contact with a spirit lamp will burn. 

Experiment 3 d. On cutting off* the flame with 
wire gauze, and looking down upon it, it will be 
seen that the section is a luminous ring, of which 
the central part is quite dark. 

Experiment 4tk. Place a wooden hoop of 6 or 
8 inches diameter, and 2 or 3 inches broad, 
upon the water of the pneumatic tub. With¬ 
in this hoop, pour some sulphuric ether, and 
set it on fire. A large flame will be obtain¬ 
ed, and it may be shown that combustion is 
not going on in its interior, by passing the 
hand through the water under the hoop, and 
up into the center of the flame, taking care 
not to touch its sides. Considerable heat 
will be felt, but it may be endured for a sec¬ 
ond or two without much inconvenience. 

408. But though the space within the flame 
be not in a state of ignition, there is oxygen contained in it, the motion 
of the inflammable vapor through the air being sufficient to cause the 
two to mingle to some extent. That oxygen is contained there may be 
proved by putting in some combustible requiring less oxygen than that 
which constitutes the basis of the flame. Thus if a piece of phospho¬ 
rus be put in a small wire cage at the extremity of a wire 
gO. bent at right angles, it may be passed up under the hoop 
into the flame : the water will drain off* through the cage, 
the phosphorus will soon melt and at last take fire and be 
consumed. Thus the inner part of the flame is not in a 
state of ignition, not because oxygen is not present, but 
because it is insufficient to form an explosive mixture with 
the inflammable gas. 

409. The luminousneSs of flames depends in general, on 
I the presence of solid matter diffused through them in an 
H incandescent state, and not to their heat. Indeed the col- 



Fig. 



orless flames, such as those of hydrogen and strong alcohol, are often 
hotter than the luminous ones; for the solid matter which makes a flame 
luminous, exerts a cooling influence proportionate to its conducting 
power. Pure hydrogen and oxygen, if set on fire in a strong glass globe, 
will give a strong light, because of the great compression. Of colored 


408. Is the flame not ignited because there is no oxygen present P 
How may it be proved that there is some oxygen within the interior of 
the flame. 

409. Why the least luminous flames are, in general, the hottest. Dif¬ 
ferent colored flames. 

16 * 















182 


INORGANIC CHEMISTRY. 


flames, the white, containing a due proportion of all the rays of the 
spectrum, is most luminous ; the colors of the rest are owing to the de¬ 
ficiency of Isome of the rays, and the consequent preponderance of oth¬ 
ers; of the colored flames, the yellow is the most luminous. 

410. The flames of common fires, candles, lamps, &c., con¬ 
sist of some of the compounds of carbon and hydrogen ; gener¬ 
ally, of several mixed together. These gases arise from the de¬ 
composition which wood, oil, and the other organic matters un¬ 
dergo by the action of heat. The carburets of hydrogen, all 
undergo decomposition at some degree of heat, the higher car¬ 
burets being more easily decomposed than light carburetted hy¬ 
drogen ; the carbon and hydrogen burn separately ; and the par¬ 
ticles of ignited carbon diffused through the flame of hydrogen, 
give it its luminous property. If the quantity of carbon is out 
of proportion to the supply of oxygen, a portion of it escapes 
unburnt, and is seen in the form of black smoke, which may be 
collected on cold surfaces, and indeed soon settles of itself; in¬ 
stances of this, are seen in the combustion of naphtha, oil of tur¬ 
pentine, and bituminous matters. But if the quantity of carbon 
be duly proportioned to the supply of oxygen, it is all consum¬ 
ed, and there is no smoke, as in the burning of strong alcohol. 

Olefiant Gas. 

411. This gas was so called from its oily appearance, when 
combined with chlorine. It is sometimes called Hydruret of 
Carbon or Per carburetted Hydrogen , and is obtained by gently 
heating, in a glass retort, a mixture of one measure of alcohol 
and three of strong sulphuric acid. The gas is freely evolved 
and is to bq collected over water. If it be cloudy at first, it 
must stand some time over the water or be agitated with water 
before use. Olefiant gas is colorless, tasteless, nearly inodorous 
and of specific gravity 0.97^ It is very little absorbed by water, 
extinguishes flame, and does not support respiration. It burns 
in the air with a white flame of greater splendor than any other 
gas; and when previously mixed with oxygen gas and set on 
fire, it detonates with exceeding violence. It is resolved into its 
elements by a succession of electric discharges, and it is more or 
less completely decomposed by passing through heated tubes, 
according to the degree of heat employed ; a low heat only re- 

410 Flames of fires, candles, &c. Cause of black smoke. Why 
there is no smoke in the burning of alcohol. 

411. Composition of olefiant gas. Synonymes. How obtained. 
Properties of olefiant gas. Products of its combustion. Decomposi¬ 
tion. 



OLEFIANT GAS. 


183 


ducing it to light carburretted hydrogen, while an intense heat 
entirely separates its elements. 

412. Olefiant gas derived its name from its property of forming an 
oil-like fluid by combination with chlorine. This combination takes 
place when the two gases are mixed, and the presence of light is not 
necessary to the re-action. The compound so formed is properly called 
hydro-carburet of chlorine , but from its volatility and etherial taste and 
odor is often denominated chloric ether. It has a sweet and aromatic 
taste, boils at 150° F. distills unchanged, and is decomposed in passing 
through red hot tubes. It produces a kind of intoxication, more resem¬ 
bling that of protoxide of nitrogen than that of ardent spirits, and has 
been recommended as a stimulant in medicine. It dissolves freely in al¬ 
cohol, but not in water; yet the alcoholic solution maybe diluted to any 
extent. The solution of chloric ether in alcohol may be obtained by dis¬ 
tilling a mixture of alcohol and chloride of lime; and it is also formed 
when chlorine gas is passsed into alcohol. If hydro-carburet of chlo¬ 
rine or chloric ether be confined under a bell glass filled' with chlorine, 
and exposed to the sun, it is decomposed; the free chloric combining 
with its hydrogen, and leaving the carbon and chlorine of the com¬ 
pound in combination, constituting perchloride of carbon. 

Bromine and iodine likewise may be brought by indirect methods, in¬ 
to combination with olefiant gas, forming the hydro-carburets of bro¬ 
mine and of iodine ; compounds bearing a close analogy to the hydro- 
carburet of chlorine. 

413. Bi-carburet of Hydrogen. This substance is a transpa¬ 
rent liquid, of an oily appearance having the odor of oil gas and 
a specific gravity of 0.85. It boils at 186° and freezes at 30 Q , 
forming crystals. It does not mix with water, but dissolves in al¬ 
cohol, ether and oils. It burns with a yellow flame giving out 
much soot; and its vapor explodes with oxygen gas or air. It 
is decomposed by chlorine in the sunshine, and by being passed 
through red hot tubes ; carbon being deposited in each case. 

414. Quadro- Carburet of Hydrogen is a liquid at zero, but 
boils a little above that point; so that at common temperatures 
it is a gas. In the fluid state it is lighter than any other liquid, 
or solid, having a specific gravity of 0.627. The density of its 
vapor is nearly twice that of air. It is combustible, giving a 
bright light and much smoke, and the vapor explodes with ox- 
ygen, producing carbonic acid and water. Chlorine gas combines 
with it producing an oily liquid, which in taste, odor, and vola¬ 
tility bear a strong resemblance to the hydrocarburet of chlorine, 


412. Derivation of the name. Compound of olefiant gas and chlo¬ 
rine. Properties of chloric ether. Solution in alcohol. Decomposition 
by means of light. Combinations of olefiant gas with bromine and 
iodine. 

413. Composition and properties of Bi-carburet of hydrogen. De¬ 
composition. 

414. Composition and properties of Quadro-carburet of Hydrogen, 
its combination with chlorine. With sulphuric acid. How analyzed ? 






184 


INORGANIC CHEMISTRY. 


but different from that substance in not yielding a chloride of car* 
bon. It is largely absorbed by sulphuric, acid, and forms with it 
a compound, the nature of which is not fully understood. Like 
the other carburets of hydrogen, it may be analyzed by detona¬ 
ting its vapor with oxygen gas^ or by passing it over red hot per¬ 
oxide of copper. 

415. Naphtha appears on the shores of the Caspian Sea, and 
also in some parts of Italy. It is also separated from petroleum 
by distillation. A substance which appears to be identical with 
it, is obtained by distilling the tar formed in the process of man¬ 
ufacturing coal gas. It is a colorless liquid when pure ; but 
generally has a yellow tinge. It is very volatile, has a strong 
odor, and burns with a bright flame and much smoke. It dis¬ 
solves in alcohol, ether, oils, and petroleum, but not in water. 
It is used to preserve potassium, sodium, &c. from contact with 
air. 

416. Napthaline is also obtained from coal tar, by sublimation 
after the naptha has been distilled off. It is a white crystaline 
solid, heavier than water, of a peculiar odor and pungent aro¬ 
matic taste. In the opeQ air it slowly evaporates like camphor. 
It scarcely dissolves in water, but does so in Naptha, in some of 
the oils, and especially in alcohol and ether. It does not burn 
readily, but when inflamed burns rapidly with much smoke. 

Acetic, oxalic and sulphuric acids dissolve napthaline forming 
solutions which have some shade of red. The solution in sul¬ 
phuric acid is a distinct acid called sulpho-naphthalic acid. This 
acid has some curious properties, but has not been applied to any 
use in the arts. Its salts are all soluble and combustible. 

417. Coal and Oil Gas. As organic substances consist of 
carbon, oxygen, hydrogen and sometimes nitrogen, among the 
numerous products of their destructive distillation, a portion of 
carburetted hydrogen is usually found. The proportion which 
it bears to the other products will, other things being equal, de¬ 
pend upon the relative quantities of oxygen and hydrogen con¬ 
tained in the substance distilled ; large doses of oxygen leading 
to the formation of more carbonic acid and water. Resinous, 
bituminous and oleaginous substances are found to contain more 
hydrogen, relatively to the oxygen, than other bodies of organic 
origin; and therefore afford, by destructive distillation, large 


415. Where is naptha found? Its properties and use. 

416. How is napthaline obtained ? Properties. Its solutions in acids. 
Sulpho-napthalic acid. 

417. Proportion of carburetted hydrogen in the products of destruc¬ 
tive distillation. Bodies which afford large quantities of inflammable 
gas. 



OLEFIANT GAS. 


185 


quantities of inflammable gas. Hence the preference is due to 
this set of compounds, in the preparation of carburetted gases 
for illumination. Coal furnishes carburetted hydrogen by being 
distilled at a red heat, in large iron retorts ; but as the bitumen 
contained in the coal is the source of the gas, the different varie¬ 
ties of coal vary greatly in their fitness for this purpose. The 
best of all is the coal of Lancashire, England; but the Rich¬ 
mond, Va. coaf yields a large quantity of gas ; while the an¬ 
thracite, such as Lehigh, Lackawana, &c. afford little or none. 
Of different specimens, that is best for producing carburetted hy¬ 
drogen, which contains the most bitumen and least sulphur. 

418. The combustion of a common lamp, or candle, is an ex¬ 
ample of the simultaneous production and consumption of oil 
gas. When flame is applied to the wick of a candle, the heat 
causes a portion of the wax or tallow to melt; by means of ca¬ 
pillary attraction, the melted portion rises in the wick, and is de¬ 
composed by the heat applied, which at the same time sets the 
resulting gas on fire. The combustion thus commenced, will 
continue so long as there is matter to feed it; the heat of the 
flame constantly melting and decomposing fresh portions of the 
candle. In this operation, the wick is to be regarded only as a 
bundle of capillary tubes, serving to convey the fluid oil to the 
point where it is to be decomposed ; a glass capillary tube, will 
answer the same purpose. The wick being surrounded by 
inflammable gas, and thus out of contact of the air, cannot burn, 
and contributes nothing to the flame. The gradual consumption 
of an ordinary cotton wick, is owing to the heat of the surround¬ 
ing flame, by which it undergoes destructive distillation; and 
the crust of carbon which results, clogs the wick, in the case of 
a lamp, and prevents the free ascent of oil to supply the com¬ 
bustion. Part of this crust of carbon, or snuff as it is called, 
perhaps is derived from carburetted hydrogen which is decom¬ 
posed by the heat in the interior of the flame. 

In the case of a candle, as soon as the exposed part of the 
wick becomes long enough to project beyond the flame into the 
air, it undergoes combustion and disappears. A very simple ex¬ 
periment will show the resolution of oil into inflammable gas by 
heat. Let a common tallow candle, with a thick wick, burn un¬ 
til the uncovered part of the wick is nearly an inch in length, 
and then extinguish it suddenly. So long as the wick contin¬ 
ues red hot, a stream of smoke will ascend from it. This col- 


418. Oil gas generated in the burning of a common lamp. Why a can¬ 
dle burns brighter for being snuffed, or a lamp for being trimmed. Why a 
candle recently extinguished may be re-lighted without the actual con¬ 
tact of flame. 



186 


INORGANIC CHEMISTRY. 


umn of smoke, contains carburetted hydrogen gas, produced from 
the tallow which the red hot wick continues to decompose ; and 
if a piece of burning paper be applied to it at the distance of two 
or three inches above the wick, it will take fire, and the flame 
running down, will re-light the candle. 

419. Carbon combines with Chlorine, Iodine and Bromine, but 
none of the compounds thus obtained are important. 


LECTURE XVIII. 


COMPOUND OF CAREON AND NITROGEN.-BORON. 

CYANOGEN. 

420. Cyanogen seems to act the part of a simple element, though 
it is a compound of Nitrogen and Carbon, or a Bi-carburet of Ni¬ 
trogen. It is a gas, obtained by the action of heat on cyanuret of 
mercury contained in a retort. It is conducted over mercury. 
The cyanuret, (formerly prusiate ,) of mercury is simply resolved 
by heat into cyanogen gas and mercury, its components. The 
vapor of mercury is condensed in the pneumatic trough, and the 
gas passed over. This gas is colorless, has a pungent odor, is 
condensible into a liquid by a pressure of 3 1-2 atmospheres ; its 
sp. gr. is 1.8. It extinguishes burning bodies, but burns when 
set on fire in the air, producing carbonic acid, and liberating ni¬ 
trogen gas ; it may also be exploded when mixed with oxygen 
gas. It is very soluble in water, and still more so in alcohol; and 
its solutions have acid properties; these, however, do not belong 
to cyanogen, but are due to acids which are generated by the re¬ 
action of the elements. 

421. Cyanogen, though a compound body, is strongly analo¬ 
gous to the simple electro-negatives : tending to combine with 
metals and other electro-positive simple bodies, and forming with 
them compounds which resemble the chlorides, ipdides, &c. ; 

419. Are there compounds of Carbon with other elements than those 
we have noticed ? 

420. Composition of Cyanogen. How obtained ? Properties. Prod- 
duct of its combustion. Its solutions. 

421. Resemblance to simple electro-negatives. Origin of the name 
Cyanogen. 




CYANOGEN, OR CARBON WITH NITROGEN. 


187 


which compounds are called cyanurets or cyanides. It also forms 
acids by uniting with oxygen and hydrogen respectively. 

The name cyanogen , (from the Greek kuanos , blue added to 
gennaoy ) implies generator of blue color ; and was given it by its 
discoverer Gay Lussac, from its being contained in Prussian 
blue , to the composition of which it is essential. The latter 
substance will be considered w hen we treat of iron, which is its 
base. 

Compounds of Cyanogen and Oxygen . 

422. Cyanous Acid. There are two compounds consisting of the same 
proportions of cyanogen and oxygen, viz. one equivalent of each , and both 
bearing the name of cyanous acid ; yet notwithstanding this identity of 
composition, their properties are entirely distinct. One of them, called 
cyanous acid of Liebig, forms salts possessing the property of detonating 
by friction or percussion; and for the sake of distinction, is frequently 
called fulminic acid. 

One of its salts is called Fulminate of Mercury. 

This compound, now much used for priming fire arms, under the name 
of percussion powder , is formed by dissolving mercury in nitric acid, and, 
after the solution has become cool, adding alcohol. In the violent action 
which ensues, nitrous and ethereal fumes are given off, and a white pre¬ 
cipitate subsides, which is the fulminating murcury. By substituting 
silver for mercury, a fulminate of silver may be obtained, which explodes 
rather more readily than that of mercury. 

423. Cyanous Acid of Wohler is formed when cyanogen gas is passed 
into a hot aqueous solution of an alkali, where water is decomposed and 
the cyanite and hydro-cyanate of the alkali are formed, as the chlorate 
and muriate are, in similar circumstances. The cyanite of potassais best 
obtained by applying a low red heat to a mixture of equal parts of ferro- 
cyanate, (triple prusiate,) of potassa and peroxide of manganese. The 
cyanogen of the ferrocyanic acid takes oxygen from the oxide of manga- * 
nease, and the cyanous acid so formed unites with the potassa. The cy¬ 
anite of potassa is then dissolved by boiling alcohol, and deposites as the 
solution cools. By dissolving this salt in cold water, and adding it to a 
solution of nitrate of silver, a cyanite, of silver is precipitated ; which, 
being well washed and suspended in water by agitation, may be decom¬ 
posed by a current of sulphuretted hydrogen gas. The sulphuret of sil¬ 
ver is precipitated, and the cyanous acid remains in solution. It is de¬ 
composed in a few hours, being acted on by the water so as to form 
carbonate of ammonia. The same resolution of cyanous acid and am¬ 
monia is effected by boiling the cyanite of potassa in water, when car¬ 
bonate of potassa remains and ammonia escapes; and if a dilute acid 
stronger than the cyanic be added to solution of cyanite of potassa, car¬ 
bonic acid escapes, while the stronger acid forms salts with the potassa 
and ammonia. If an undiluted acid be used, the cyanous acid remains 
undecomposed a short time, and gives an odor like vinegar. 


422. Two compounds called cyanous acids. Cyanous acid of Liebig. 
Formation of fulminate of mercury. Fulminate of silver. 

423. How is the cyanous acid of Wohler formed ? Anhydrous cya¬ 
nous acid. 



188 


INORGANIC CHEMISTRY. 


Anhydrous cyanous acid was obtained by M. Wohler, by distilling 
anhydrous cyanic acid, and collecting the products in cool vessels. 
Cyanous acid thus obtained is a colorless liquid, very volatile, which 
forms a soluble salt with baryta, and an insoluble one with oxide of sil¬ 
ver and some other metallic oxides ; the latter being totally soluble in 
nitric acid. 

424. Cyanic Acid , consists ofl Cyan.2G added to 2 ox. 16 = 42. 

This compound is formed by boiling bichloride of cyanogen with water. 
Water is decomposed, its hydrogen combining with the chlorine and its 
oxygen with the cyanogen. By the evaporation most of the muriatic 
acid is repelled, and on cooling the cyanic acid crystalizes. The crystals 
are colorless and at first, transparent; but they become opake if exposed 
to air, and give off water by gentle heat. This acid is nearly tastless 
and volatile ; but if subjected to strong heat a portion of it is resolved in¬ 
to pure cyanous acid and oxygen. It is decomposed by potassium form¬ 
ing with its oxygen, both potassa and cyanuret of potassium. 

Compounds of Cyanogen and Hydrogen. 

425. Hydro-cyanic Acid or Prussic Acid, consists of 1 Cyan. 26 
added to 1 Hyd. 1 = 27. This acid by its combination with the 
oxide of iron produces Prussian blue. It was discovered by 
Scheele in 1780, but he only obtained it in solution with a large 
proportion of water- Gay Lussac first obtained it pure. It has 
never been found in nature ; though it is said to exist in the 
leaves, flowers, and kernels of the peach, in bitter almonds, and 
in the bark of certain plants. Thenard however, speaks doubt¬ 
fully of the existence of this acid in those vegetable substances. 
Most writers are silent on the subject; but Professor Silliman 
says, that if peach, laurel, or almond water be combined with 
lime or an alkali, it will precipitate Prussian blue from a solution 
of iron. It is produced during many chemical operations ; it re¬ 
sults in some degree whenever any substance vegetable or animal 
which contains nitrogen is distilled ; it is produced when these 
substances are calcined with potash or soda, and the residue is 
mingled with acids and many metallic solutions ; it results from 
the action of nitric acid on vegetable and animal substances, and 
and of ammonical gas upon burning charcoal. 

426. Hydro-cyanic acid is liquid, colorless, and corrosive. Its 
odor is strong, resembling that of peach blossoms. It reddens 
litmus feebly. It is very volatile ; boils at 79° F. and freezes at 
zero. The voltaic pile decomposes it, the hydrogen going to the 

424. Composition of cyanic acid. How formed. Its crystals. Solubil¬ 
ity in water and acids. Properties. Decomposition. 

425. Compounds formed by hydro-cyanic acid with oxide of iron. Dis¬ 
covery of this acid. Where found. How produced. 

426. Properties of hydro-cyanic acid. Decomposition by the voltaic 
pile, &c. Action on the animal system. 



HYDRO-CYANIC ACID OR PRUSSIC ACID. 


189 


negative, and the cyanogen to the positive pole. Its vapor is in¬ 
flammable and detonates with oxygen gas. In volume this acid 
consists of 1 vapor of carbon, 1-2 of hydrogen, and 1-2 of nitro¬ 
gen condensed into one volume. Its action on the animal system 
is very destructive, as has been proved by the experiments of 
Orfila, Magendie and others. The end of a small tube having 
been touched to a drop of this acid was put into the mouth of a 
dog ; the animal made two or three rapid inspirations and fell 
dead. One drop of the acid was applied to the eye of a dog, and 
the effects were scarcely less sudden than in the other case. 
Prussic acid, says Thenard, is without doubt, the most active and 
mortal of all known poisons, and a knowledge of its effects, ren¬ 
ders less extraordinary those sudden deaths by poison so common 
in the annals of Italy. It is by destroying the sensibility and the 
power of voluntary contraction of the muscles that it acts upon 
animals with warm blood, and the death which it occasions is sud¬ 
den in proportion as the circulation is more rapid, and the organs 
of respiration more extended. 

427. When introduced with some iron under a bell glass with 
mercury, and adding water to the mixture, it gradually disen¬ 
gages hydrogen gas, and prussian blue is produced. The produc¬ 
tion of this color furnishes a method of detecting the poison when 
used criminally. Portions of the stomach of a person supposed to 
be destroyed by prussic acid, are cut up and introduced into a re¬ 
tort with water slightly impregnated with sulphuric acid. If, on 
testing them with a prepared solution of the protoxide of iron, 
prussian blue is formed, there must have been present, hydro¬ 
cyanic acid. The sulphate of copper, furnishes a still more satis¬ 
factory test. 

Hydro-cyanic acid unites with most alkaline bases, forming salts 
which are called prussiates or hydro-cyanites. These salts are 
poisonous ; they are decomposed by carbonic acid. Attempts 
have been made to introduce prussic acid into use as a medical 
agent; but it has hitherto been considered of too dangerous a 
nature, to be employed in any considerable degree. 

Compounds of Cyanogen and Chlorine. 

428. Chloride of Cyanogen , sometimes called cyanuret of chlorine , and 
cyanide of chlorine , was discovered by Berthollet; he named it oxij- 
prussic acid , on the supposition that it was composed of prussic acid and 
oxygen. Gay Lussac, who afterwards studied its nature, called it 
chlorocyanic acid. 

427. Tests of the presence of hydro-cyanic acid. Hydro-cyanites. 

428. Synonymes of chloride of cyanogen. How first obtained pure 
Properties. Its precipitates with protoxide of iron. 



190 


INORGANIC CHEMISTRY. 


It was not obtained in purity, until about the year 1827, when it was 
procured by exposing powdered cyanuret, (prussiate of mercury,)* moist¬ 
ened with water, to the action of chlorine gas contained in a closely 
stopped bottle. After a few hours, the color of the chlorine disappeared, 
the cyanuret of mercury was converted into the solid bi-chloride of mer¬ 
cury, (corrosive sublimate,) and a gaseous chloride of cyanogen filled the 
bottle. This acid is a limpid, colorless liquid at 10° ; and above this, at 
the common pressure, it is a gas. When enclosed in sealed tubes, it is 
liquid at 68° Fahrenheit, being then under the pressure of 4 atmospheres 
created by its own vapor. It is poisonous to the animal system ; the va¬ 
por is offensive and injurious to the eyes ; its taste is caustic. It is very 
soluble in water, and alcohol; it is absorbed by alkalies, and if an acid 
be then added, an effervescence takes place, carbonic acid is evolved, 
and ammonia, muriatic acid, and probably hydrocyanic acid are formed. 
It precipitates green, the solutions of the protoxide of iron ; this precipi¬ 
tate becomes a beautiful blue by the addition of sulphuric acid, or sul¬ 
phate of iron ; but if potassa be mixed with the chloride of cyanogen be¬ 
fore adding the salt of iron, this precipitate is not formed. 

429. Per chloride (or bichloride) of Cyanogen. We have, in this com* 
pound, twice as much cMorine, as in the chloride of cyanogen; that is, 
2 atoms of chlorine to 1 of cyanogen. It was discovered by M. Serullas, 
and is prepared by adding anhydrous prussic acid, to dry chlorine. It is 
solid at common temperatures. Its vapor is acrid and poisonous. It is 
rapidly decomposed by hot water, forming muriatic and cyanic acids. 

Compounds of Cyanogen with Bromine and Iodine. 

430. Cyanogen unites with bromine forming a compound cal¬ 
led the Bromide of Cyanogen. It resembles prussic acid in its 
noxious qualities. On account of the danger, attending its pre¬ 
paration, and the difficulty of obtaining a sufficient supply of 
bromine, it has hitherto been little studied. 

The Iodide of Cyanogen is obtained by heating a mixture of 1 
part of iodine , and 2 of the cyanuret of mercury. The violet va¬ 
pors of iodine which first appear, are succeeded by white fumes, 
arising from the decomposition of the cyanuret; these, when 
condensed in a receiver, settle upon its sides resembling flocks of 
cotton. The iodide of cyanogen is composed of 1 equivalent of 
cyanogen 26 with 1 of iodine 124, its representative number is 
therefore 150. 

BdRON. 

431. The discovery of this simple element is, by English 

* Sometimes called cyanide of mercury. 


429. Composition of the perchloride of cyanogen. Discovery, prepa¬ 
ration and properties. 

430. Bromide of eyanogen. Iodide of cyanogen. 

431. Discovery of boron. Manner in which it was obtained by Davy. 
By Gay Lussac and Thenard. 



BORON. 


191 


Chemists, ascribed to Sir Humphrey Davy, who, in 1807 ob¬ 
tained it by exposing boracic acid to the action of 500 pairs of 
galvanic plates. The French Chemists assert that it was dis¬ 
covered in 1809 by Gay Lussac and Thenard. It appears that, 
though Davy discovered the existence of such an element, he 
did not obtain it in sufficient quantity to determine its properties. 

Thenard says, “ According to Mr. Davy, when boracic acid is brought 
in contact with the two poles of a very powerful battery, there appears 
at the negative pole, a small brown spot, which he attributes to the pres¬ 
ence of boron, while the oxygen of the acid appears at the positive pole. 
But it is not possible, by this means to obtain an appreciable quantity of 
boron.”* It was obtained by Gay Lussac, and Thenard, by heating 
equal parts of boracic acid, and potassium, in a porcelain or copper tube 
hermetically sealed at one end. The tube is heated to redness, one part 
of the acid is decomposed, giving off oxygen to the potassium; a portion 
of oxygen not decomposed, combines with the newly formed oxide of 
potassium ; and the result of the operation, is the sub-borate of potassa, 
and boron. This salt is then dissolved into water, and the boron pre¬ 
cipitated.t Berzelius recommends as the easiest and most economical 
mode of preparing it, to decompose the fluo-borate of potassa, by heating 
with potassium. 

432. Boracic acid is put with the potassium into a copper cup, sup¬ 
ported by a cylinder of copper C ;—A A are rods which support a large 
receiver. One of the pipes, P, communicates with an air pump. The 
air being exhausted from the receiver, an iron rod heated to redness, is 
introduced through the cylinder B, until it touches the bottom of the cup. 
The cup is soon heated and a deep red flame appears to cover the whole 
mass. On cooling, it is found that the potassium has taken from the 
acid its oxygen, forming the oxide of potassium, (potash,) while pure 
boron remains. 

433. Boron appears at ordinary temperatures, as an olive 
green powder. It is insipid to the taste, inodorous, and inso¬ 
luble, not only in water, but in ether, alcohol, or oils. It is a 
non-conductor of electricity ; absorbs oxygen at a high tempera¬ 
ture, giving off light, and it burns spontaneously in chlorine gas. 
It decomposes nitric acid, taking a portion of its oxygen, and thus 
forming boracic acid, while nitric oxide is liberated. The weight 
of the atom of boron, is the same as that of oxygen, viz. 8. 

Compounds of Boron and Oxygen. 

434. Boracic Acid. 1 bor. 8 added to 2 ox. 16=24. 

* Thenard Traite de Chimie, Tome I. p. 212. 

t Traite de Chimie, Tome II. p. 137. 


432. Dr. Hare’s method of obtaining boron from boracic acid. 

433. Properties ofboron, &c. 

434. Composition of boracic acid. From what first obtained ? Dis¬ 
covery. Synonymes, &c. How obtained from the borate of soda? 
When discovered to be compound ? 



192 


INORGANIC CHEMISTRY. 


Dr. Hare’s Apparatus for obtaining Boron from Boracic Acid. 


, Fig. 81. 



Boracic acid is the only known compound of boron and oxy¬ 
gen. It was first obtained from Borax , or the sub-borate of 
soda ; and from this it derives its name. Borax, which is a na¬ 
tive alkaline salt, will be treated of under the head of salts. 

Boracic acid was discovered by Homberg, a Chemist of the 
Academy of Sciences of Paris in 1702. It was for many years 
known by the name of Homberg'’s sedative salt , and was obtained 
from the borate of soda by means of acids, which, uniting with 
the soda, liberated the boracic acid. Until its decomposition by 
Davy and the French Chemists about 1S08, it was regarded as a 
simple body. It was then found to be composed of oxygen and 













BORON AND OXYGEN. 


193 


a very combustible substance which was named boron ; the lat¬ 
ter, as it cannot, by any known methods, be decomposed, is now 
ranked among the simple elements. 

435. Boracic acid is found in solution, in the hot springs of 
Lipari, in many of the small lakes of Tuscany, and in concretions 
upon their borders. It exists extensively in lakes in the East 
Indies, though usually in combination with soda, forming borax. 
It is found in the crafers of volcanos, and is a constituent of 
boracic tourmaline, and some other minerals. So common has 
this acid become in commerce, that it is sometimes used with 
soda in the manufacture of borax. 

For chemical experiments, and medicinal purposes, boracic acid is 
usually obtained from the decomposition of borax, or the borate of soda 
by sulphuric acid, and boiling water, sulphate of soda is formed, and 
boracic acid is liberated ; the latter, on evaporating and cooling the so¬ 
lution, is precipitated in shining, scaly crystals. The acid being now 
combined with some water ; is a hydrate ; but, by exposure to a strong 
red heat, it melts into a transparent glassy substance. 

Vitrified boracic acid should be preserved in well stopped bottles, 
otherwise it absorbs water from the air, and loses its transparency. In 
the state of a hydrate, its specific gravity is 1.48, in the purified or vitre¬ 
ous state, it is 1.80. It is inodorous, and has a bitter, rather than an 
acid taste. It effervesces with the alkaline carbonates, though when ap¬ 
plied to turmeric paper, it acts like an alkali, giving it a brown color ; it 
reddens vegetable colors. In solution with alcohol, it burns with a 
beautiful pale green flame. 

The form of crystals of boracic acid are hexahedral, they have a pearly 
whiteness, and feel smooth and oily like spermaceti. They contain, 
Boracic acid 24, or one equivalent. 

Water 18, “ do. 

Equiv. of boracic acid 42. 

436. Boracic acid, like hydrochloric, (muriatic,) and hydrofluoric acids, 
was long ranked among undecomposed bodies ; but like them, it is now 
found, both by analysis and synthesis, to donsist of an inflammable basis, 
uniting to a supporter of combustion ; but while the base of boron com¬ 
bines with oxygen to form boracic acid, we have found the hydro-chloric 
acid having inflammable hydrogen for its base, united to the supporter 
of combustion, chlorine. The hydrofluoric may still be regarded as of a 
doubtful nature, though at present, it is usually ranked among the hy- 
dracids. 


Compounds of Boron with Chlorine and Fluorine. 

437. The chloride of boron is formed by the combustion of boron in 
chlorine gas. As one equivalent of boron 8, unites with 2 equivalents 
of chlorine, 72, the representative number of this chloride is 80; and it 
is usually called, on account of its composition, the bi-chloride of boron. 

435. Exists in nature. How obtained for chemical experiments and 
medicinal purposes ? Properties. Crystals of boracic acid. 

436. Acids which were formerly ranked among undecomposed bodies. 

437. Chloride of boron. 

17 * 



194 


INORGANIC CHEMISTRY. 


Sir Humphrey Davy first observed, that boron takes fire spontaneously 
in an atmosphere of chlorine, and burns with a vivid light. Berzelius 
afterwards commenced a series of experiments, to ascertain the nature 
of the compound formed by this combustion. He found it to be a gas 
which is rapidly absorbed by water, when double decomposition takes 
place, and hydro-chloric and boracic acids are produced. M. Dumas and 
M. Despretz have found that the bi-chloride of boron may be generated 
by the action of dry chlorine on a mixture of boracic acid and charcoal, 
heated to redness in a porcelain tube. 

438. The fluoride of boron is generally known among Chemists, by the 
name of fluobdric acid gas; but its nature and composition, is still a sub¬ 
ject of doubt. If fluorine could be obtained in an uncombined state, and 
then united with the inflammable boron, the result would be an undoubt¬ 
ed fluoride of boron; but, as fluoric acid has not yet been decomposed, 
its combinations are still regarded as of an uncertain character. “ The 
chief difficulty in determining the nature of hydro-fluoric acid,” says 
Turner, “ arises from the water of the sulphuric acid which is employed 
in its preparation. To avoid this source of uncertainty, Gay Lussacand 
Thenard made n mixture of vitrified boracic acid, and fluor spar, and ex¬ 
posed it, in a leaden retort, to heat, under the expectation that as no 
water was present, anhydrous fluoric acid would be obtained. In this, 
.however, they were disappointed; but a new gas came over, to which 
they applied the term of fluo-boric gas.” The gas may be formed by the 
action of hydro-fluoric acid on a solution of boracic acid. Some suppose, 
that in the decomposition of fluor spar, (fluoride of calcium,) the two 
substances interchange elements, the calcium and oxygen uniting to form 
lime, and a portion of free boracic acid forming with the lime, while 
borate of lime, boron, and fluorine, enter into a direct combination. The 
discoverers of this gas regarded it as a compound of fluoric and boracic 
acids, and therefore named it fluo-boracic acid, and the salts which it 
forms with alkalies, fluoborates. 

While fluoric acid has a powerful action upon glass, the fluo-boric acid, 
(or fluoride of boron,) has no effect upon it, its affinity for silex being neu¬ 
tralized by the presence of boron. It carbonizes animal and vegetable 
substances, extinguishes flame, and is irrespirable. When absorbed by 
water, for which it has great affinity, it forms a dense, fuming, and cor¬ 
rosive liquid, somewhat resembling sulphuric acid, equally powerful in 
its effects on vegetable blues. 


438. Fluoride of boron. Synonyme. Its doubtful nature. Experi¬ 
ment of Gay Lussac and Thenard. Explanations. Fluo-borates. Pro¬ 
perties of fluoride of boron. 



SILICON. 


195 


LECTURE. XIX. 

SILICON.-PHOSPHORUS. 

SILICON. 

439. We should, reasoning a priori, 'expect that the simple, 
or undecomposible elements might be more easily understood 
than compounds ; but this is not the case in many instances. 
Indeed, most of these elements, except some of the metals, are 
found in nature only in combination, from which, science alone 
has taught us how to disengage them. Thus, though silicon, in 
combination with oxygen, forms silex, one of the most abun¬ 
dant substances in nature, it has remained hidden from our ob¬ 
servation, till within a few years ; and it is only by difficult and 
complicated processes, that it has been obtained in quantities 
sufficient to render observations and experiments upon it, of a 
definite and satisfactory nature. 

440. Sir Humphrey Davy by experiments with silex, or sili¬ 
ceous earth and heated potassium, discovered that the former is 
a compound of oxygen and a peculiar base, to which, on the sup¬ 
position of its being a metal, he gave the name of silicium , cor¬ 
responding to calcium and potassium, the metallic bases of lime 
and potash. This substance has continued to be classed among 
the metals, until Berzelius has proved that it is infusible, devoid 
of metallic lustre, a non-conductor of electricity, and in short is 
destitute of all the distinguishing characteristics of metals. On 
account of its resemblance to boron and carbon in being combus¬ 
tible, it is by late Chemists, ranked among the non-metallic com¬ 
bustibles, and in corresponding terminology called silicon. Its 
chemical equivalent is the same as that of oxygen, viz. 8. 

441. Berzelius states,* that pu?e silicon is of a dark brown 
color, exhibiting no metallic lustre even by rubbing, and like 
earthy bodies, opposes resistance to the body against which it is 
rubbed. It leaves a stain upon glass vessels, adhering strongly 

* See Mcmoirc de Berzelius, Annals de Cliimie ,Tome xxvii. p. 341. 
Those who have not access to the original memoir may find an abridged 
translation in the author’s Dictionary of Chemistry, pp. 414—416. 

439. Why simple bodies are less readily understood than compound. 
Obscure nature of silicon. 

440. Discovery of the compound nature of silex. Change of the 
name silicium to silicon. 

441. Properties of silicon. 



196 


INORGANIC CHEMISTRY. 


to them when dry. It is destitute of taste or odor, and a has 
no action upon vegetable colors. It is a bad conductor 
of heat and electricity, burns neither in the air nor in oxygen, 
and remains unaffected by the flame of the blow pipe. It de¬ 
composes water, and becomes converted into silex by its union 
with oxygen. 

442. Silicon was first ob¬ 
tained pure by Berzelius in 
1824, by the action of po¬ 
tassium on fluo-silicic acid 
gas. Dr. Hare has invent¬ 
ed a convenient apparatus 
for this purpose. A bell 
glass is so fixed that it may 
be connected with an air 
pump; a platinum wire is 
suspended within the bell 
glass, and a cup containing 
potassium hangs just below 
the wire. The air being 
exhausted from the bell 
glass, fluosilicic acid, (or 
fluoride of silicon,) is ad¬ 
mitted, and the platinum 
wire ignited by an electric 
spark. The potassium is 
inflamed, and in burning 
decomposes the fluosilicic 
acid, giving rise to a pecu¬ 
liar deep red flame, and 
chocolate colored fumes, 
which condense into flakes 
forming, (except in color,) 
a miniature representation 
of a snow storm. On 
washing the precipitate which is collected after this combustion, pure 
silicon , which is insoluble, is obtained, the residue being chiefly fluoride 
of potassium. 

Compound of Silicon and Oxygen. 

443. The only compound of oxygen and silicon is composed 
of 1 atom of silicon, 8 to 1 of oxygen, 8=16. By some Chem¬ 
ists it is termed silicic acid , from its analogy with boracic and 
fluoric acids, and because, like acids, it saturates the alkalies. 
It was named the oxide of silicon , when silicon was considered as 
a metal. The change of its classification will, very properly 


442. Dr. Hare’s method of obtaining silicon from fluo-silicic acid. 

443. Composition of silicic acid. Its synonymes. Its existence in na¬ 
ture. 














SILICON AND OXYGEN. 


197 


alter the names of its compounds. The oxide of silicon is some¬ 
times called silex , the Latin name for flint; in the labratory it is 
known as silica . It has long been known in the arts, and was 
called by ancient Chemists, vitrifiable earth , because it entered 
into the composition of glass. It is extremely diffused in na¬ 
ture, being the principal constituent of most mineral substances. 
It is found nearly pure in flint, quartz crystals, calcedony, and 
various other minerals. The purest white sand contains little 
else. 

444. For common purposes, flint or rock crystal, heated to a 
red heat, and thrown into water and pulverized, affords silica 
sufficiently pure. In order to obtain perfectly pure silica, the 
pulverized article is melted in a crucible with three or four times 
its weight of potassa and the alkalies ; the siliceous mass thus 
formed, being dissolved in diluted muriatic acid, a precipitate of 
pure silica will be obtained, which must be repeatedly washed 
with distilled water, and then dried. 

445. Silica is a light, white powder, insipid, tasteless, and 
harsh to the touch. It has no effect on vegetable colors, is not 
caustic, and has no alkaline properties, except its affinity for one 
acid, viz. the fluoric, which acts powerfully upon it. It resem¬ 
bles acids in combining with fixed alkalies and metallic oxides, 
and is therefore sometimes termed silicic acid, and its compounds 
with alkaline bases, silicates. 

When dry, silica neither dissolves in water nor is absorbed by 
it, though in its nascent state, or when just precipitated, it dis¬ 
solves freely in this liquid. It is a remarkable fact, that silica, 
on evaporation, should thus lose its property of dissolving with 
water; and this offers an explanation of the vast collection of 
siliceous crystals which nature presents in cavities of quartz, 
agate, and many other minerals of the same class; and which 
may be regarded as hydrates of silica , in which the water of crys- 
talization exceeds in volume the mass of silica. In some hot 
springs as the geysers of Iceland, silica is found in solution, 
which is promoted by the soda contained in their waters. 

446. When silica is fused with a large portion of potassa, a 
vitreous mass'is produced which is soluble in water. This was 
known by the old writers under the name of liquor of flints. If 
the proportion of silica and alkali be reversed, (that is, a small 
portion of alkali added to silica,) and the mixture be fused, the 
result is a transparent, brittle compound which is insoluble in 
water, and is attacked by no acid except the hydro-fluoric ; 


444. Mode of obtaining it. 

445. Properties. Silicates. Its action with water. 

446. Liquor of flints. Glass. Cause of varieties of glass. 



198 


INORGANIC CHEMISTRY. 


this compound is glass. u Every kind of glass is composed of 
silica and an alkali, and all its varieties are owing to differences 
in the proportions of the constituents, to the nature of the alkali, 
or the presence of foreign matter. Thus, green bottle glass is 
made of impure materials, such as river sand, which contains 
iron, and the most common kind of kelp or pearlashes. Crown 
glass for windows is made of purer alkali and sand which is free 
from iron. Plate glass for looking glasses is composed of sand 
and alkali in their purest state, and in the formation of flint glass, 
besides these pure ingredients, a quantity of red lead or litharge 
is emyloyed.”* Black oxide of manganese improves the trans¬ 
parency of glass, by oxidizing any carbonaceous substances in 
the materials used ; and boracic acid or borax [are employed in 
making imitations of gems. Silica is also Used in the composi¬ 
tion of porcelain ; as pure clay without any silicious earth would 
shrink too much for this purpose. 

Compounds of Silica with Chlorine , Sulphur and Fluorine. 

447. Chloride of Silicon is formed by the combustion of silicon in chlo¬ 
rine gas. It is liquid, limpid, and volatile, evaporating in open vessels, 
in the form of a white vapor. Its odor resembles that of cyanogen. 
Water changes it into muriatic acid and silica. 

448. Sulphuret of Silicon. Silicon when heated with the vapor of 
sulphur, unites with it, forming a white earthy looking substance. Wa¬ 
ter converts it into sulphuretted hydrogen and silica. The former es¬ 
capes with effervescence, the latter dissolves. 

449. Fluoride of Silicium , or Fluo-silicic Acid Gas is composed of 1 
Silicon 8 added to Fluor 10=18. 

In treating of hydro-fluoric acid, especially its action upon glass, we 
found that in decomposing that substance a peculiar gas was generated. 
This is the fluo-silicic acid. It is a colorless gas, of a strong odor and 
caustic taste. It extinguishes combustion, is irritating to the lungs, and 
is not decomposed by heat. Its specific gravity is 3.57. Water acts 
upon it, precipitating silica in a gelatinous state. It forms white fumes 
with the atmosphere by combining with aqueous vapor. When distilled 
in a receiver containing water, it becomes covered with a silicious crust, 
which at length covers the water, and it is necessary to shake the vessel 
and break this crust that the condensation may not thus be prevented. 
Moist Substances exposed to this gas, become encrusted with it, so as to 
resemble petrifactions ; thus insects, reptiles, and vegetable substances, 
by being moistened and placed in an atmosphere of this gas may be 
made to appear like natural fossils. 

^Turner. 


447. Formation and properties of chloride of silicon. 

448. Formation of sulphuret of silicon. 

449. Composition of fluo-silicic acid. When produced. Properties. 
Action with water. How prepared for experiments ? Chan ore when 
dissolved in water. 



PHOSPHORUS. 


199 


It may be prepared for experiments by heating in a retort three parts 
of fluor spar and two of silica, with an equal weight of sulphuric acid; 
it must be collected over mercury. When dissolved in water; it becomes 
the silico-hydro fluoric or silicatcd fluoric acid; the hydrogen of the wa 
ter combining with the fluorine, and the oxygen with the silicon. 

PHOSPHORUS. 

450. Phosphorus combines so readily with oxygen and other 
substances that it is not found pure in nature. It is solid, but so 
soft and flexible that it maybe bent with the fingers like wax. It 
may be cut with a knife. Its color when pure is white, but on 
exposure to air and moisture it assumes a brownish hue. When 
excluded from contact with the air, light gives it a red color. Its 
specific gravity is 1.77. Its combining equivalent is 12. Its 
odor is feeble, somewhat resembling that of hydrogen gas. It is 
always luminous in the dark, hence its name—the light-bearer, 
from the Greek phos light, phero to bear. 

451. Phosphorus was discovered in 1669, by Brandt an al¬ 
chemist of Hamburgh in his search for the philosopher's stone , or 
the art of converting the common metals into gold and silver. 
He imagined that he might effect this transmutation by the aid of 
an extract obtained from animal substances. Though disappoint¬ 
ed in his principal object, he obtained a new and wonderful sub¬ 
stance shining with its own light, and burning with surprising 
brilliancy. Surprised at the appearance of this new body he 
sent a portion of it to Kunkel a German Chemist, who hastened 
to show it to his friend, Kraft of Dresden. The latter lost no 
time in repairing to Hamburgh, and succeeded in buying the se¬ 
cret of preparing this new and singular substance. Kunkel la¬ 
bored to ascertain by experiment, what his friends would not con¬ 
fide to him, and succeeded, after several years of fruitless at¬ 
tempts, The preparation of phosphorus, however, remained a 
secret until 1737, when a stranger in Paris, communicated it to 
a committee of the French Academy of sciences. But the meth¬ 
od then used was tedious and imperfect. In 1769, Gahn of Swe¬ 
den, in connection with Scheele, published a newly discovered 
process for obtaining phosphorus by distillation of bones. This 
is the one now generally followed. Phosphorus being thus ea¬ 
sily obtained, chemists were able to study its properties. Much 
is due to the labors of M. Pelletier, who first combined it with 
sulphur and many of the metals ; to Lavoisier, who investigated 
its combination with oxygen ; to Dulong and Davy, who studied 

450. Why is phosphorus not found pure in nature? Its physical 
properties. Derivation of the name. 

451. History of the discovery of phosphorus and its combinations. 



200 


INORGANIC CHEMISTRY. 


its different acids, and to Berzelius, who has examined the com¬ 
binations of these acids, with different bases. 

452. The solid parts of the bones of animals consist, princi¬ 
pally, of the phosphate of lime, a salt formed by the union of 
phosphoric acid and lime. Phosphoric acid is a compound of 
phosphorus and oxygen. From the decomposition of the phos¬ 
phate of lime in bones, phosphorus is obtained. The usual 
process is, to digest in sulphuric acid a quantity of calcined 
bones (that is bones burnt in an open fire,) reduced to powder. 
The phosphate of lime is decomposed by the sulphuric acid, 
which, uniting with the lime forms sulphate of lime; the disen¬ 
gaged phosphoric acid being now mixed with powdered charcoal, 
and strongly heated in an earthen retort, parts with its oxygen to 
the charcoal, forming carbonic acid, while [phosphorus passes 
over in the form of vapor, and may be collected by placing the 
beak of the retort under a receiver filled with water. When 
first obtained it is of a red color, owing to the presence of the 
phosphoret of carbon, from which it may be purified by another 
distillation. 

453. Phosphorus is highly inflammable, and gives off a gar¬ 
lic odor when burning. When exposed to the air at common 
temperatures it undergoes slow combustion, appearing in the 
light as a white smoke and in the dark as a beautiful blue lumi¬ 
nous cloud. It should be kept in water, as a slight degree of 
heat, in the open air readily kindles it to a flame. It melts at 
99° F. takes fire at 108° ; and volatizes at 219°. 

454. Perhaps no substance affords such a variety of brilliant experi¬ 
ments, especially for an evening’s exhibition, as phosphorus. 

Ex. 1st. Words or figures drawn on the wall of a dark and warm room 
with a stick of phosphorus will leave traces, which in the night will ap¬ 
pear like fire. 

Ex. 2nd. A few- grains of phosphorus in the bottom of a wine glass 
will burn with brilliancy, and a succession of detonations, by pouring 
on water and sulphuric acid. 

Ex. 3 d. Oil, in which phosphorus has been dissolved, when rubbed 
on the face and hands, exhibits the appearance of a lambent flame, play¬ 
ing over the features, accompanied with luminous clouds and flashes. 
Unless the phosphorus is entirely dissolved, this may prove a dangerous 
experiment; severe burns have been thus caused. 


452. Mode of obtaining phosphorus. 

453 Inflammable nature of phosphorus &c. 
454. Experiments with phosphorus. 



PHOSPHORUS. 


201 


Ex. 4th. The combustion of phosphorus 
in oxygen gas , or even an enclosed portion 
of atmospheric air, is attended with a splen¬ 
dor too great for the eye to endure. Dur¬ 
ing combustion dense white vapors like 
flakes of snow will fill the jar. These va¬ 
pors are phosphoric acid , consisting of phos¬ 
phorus and oxygen. 

Ex. 5th. Eudiometry may be performed by 
consuming the oxygen of the air icith phos¬ 
phorus. If a cylinder of phosphorus be 
supported upon a wire within a glass mat¬ 
rass, inverted in a jar of water, the included 
air is gradually absorbed. In order to de¬ 
termine the quantity of oxygen in the air, 
we have only to ascertain the ratio between 
the quantity absorbed, and the quantity in¬ 
cluded. This object may be attained by 
weighing the matrass when full of water, 
and when containing that portion only 
which rises into it in consequence of the 
absorption. As the weight in the first case 
is to the weight in the last, deducting the 
weight of the glass , in both cases ; so will 
100 be to the number of parts, in 100 of at¬ 
mospheric air, which consist of oxygen gas. 
If the neck of a vessel of this kind hold 
about one fourth as much as the bulb, 
by graduating the neck so that each divis¬ 
ion will represent 1-100, part of the whole 
capacity, the result may be known by in¬ 
spection.* 

455. Phosphorus does not, at the 
ordinary pressure, burn in oxygen gas 
at a temperature below 80° ; but if the 
pressure is diminished, it becomes lu¬ 
minous in the dark and burns. Ni¬ 
trogen by rarefying the oxygen of the 
atmosphere, acts like the diminution 
of pressure, and singularly favors the 
combustion. In pure nitrogen, phos¬ 
phorus is not luminous at any temper¬ 
ature. 

Phosphorus forms combinations with most other combustible 
bodies. Combined with oxygen it enters into the composition 
of many minerals, and forms a large portion of the animal frame. 
It is employed in the arts for the construction of phosphoric 



Hare’s compendium. 


455. Circumstances under which phosphorus burns in oxygen gas &c. 
Combinations of phosphorus. Uses. 

18 





















202 


INORGANIC CHEMISTRY. 


matches, and in Chemistry for the analysis of air and the prepa¬ 
ration of phosphoric acid. It is a violent poison, though it is 
sometimes used in medicine in very small doses. 

Combinations of Phosphorus and Oxygen. 

456. There is an uncertainty with respect to the number of 
combinations of these two elements. Dr. Turner remarks that 
“ under the term phosphoric acid, Chemists have hitherto includ¬ 
ed two distinct acids, phosphoric , and pyro-phosphoric , compounds 
which afford an instance of a fact of much importance to the 
atomic theory: viz. That two substances may consist of the same 
ingredients , in the same proportion , and yet differ essentially in 
their chemical properties.”* 

457. There are three known acid combinations of phoshorus 
and oxygen, which contain different proportions of their constit¬ 
uent elements. 

1‘. Phosphoric acid , 1 Phos. 12 added to 2 Ox. i6 = 2S. 

2. Phosphorous acid , 1 Phos. 12 added to 1 Ox. 8 ==23. 

3. Hypo-phosphorous acid , 2 Phos. 24 added to 1 Ox. 8=32. 

458. Phosphoric acid may be obtained by the combustion of 

phosphorus in oxygen gas, (see IT 454, ex. 4th.) It may also be 
obtained by burning phosphorus in an enclosed portion of atmos¬ 
pheric air, occasionally raising the receiver, in order to let in 
fresh supplies of air, until all the phosphorus is consumed, 1 grain 
of phosphorus requires about 15 cubic inches of common air, and 
of course about 4 cubic inches of oxygen for its saturation. 
Phosphoric acid may also be prepared by the action of sulphuric 
acid on calcined bones. 

459. This acid is white, solid, inodorous, and heavier than 
water. It is soluble in water, dissolving with a hissing noise, 
and forms, if concentrated, a dense oily liquid. 

“ On heating the solution in a platinum vessel the greater part of the 
water is driven off; the residue freezes at below red heat, and concretes 
on cooling into a brittle glass, called glacial phosphoric acid. This sub¬ 
stance is a hydrate which cannot be decomposed by fire ; for on exposing 

* See IT 422, remarks upon the two kinds of cyanous acid. 


456. Dr. Turner’s remark respecting phosphoric and pyro-phosphoric 
acids. 

457. Names and composition of acid compounds of phosphorus and 
oxygen. 

458. How may phosphoric acid be obtained ? 

459. Properties. Glacial phosphoric acid, &c. 



PHOSPHORUS. 


203 


it to a strong red heat with a view of expelling the water, the compound 
itself is volatilized, and in open vessels sublimes with considerable 
rapidity.” 


Phorphoric acid, though powerful in re¬ 
spect to its entirely sour taste, its action on 
vegetable blue colors, and its effect in neu¬ 
tralizing alkalies, does not decompose ani¬ 
mal matter like nitric and sulphuric acids. 

460. Phosphoric acid may be decompos¬ 
ed by heating it with charcoal. Let a 
mixture of the two substances be put into 
the retort a, and placed over the furnace 
b, the beak of the retort being immersed in 
the basin of the water, c. The phosphoric 
acid loses oxygen, which, uniting with 
the vapor of carbon from the charcoal, 
forms carbonic acid gas : the phosphorus 
passes over, being volatilized when the re¬ 
tort is at a red heat, and appearing in the 
basin, in the form of a reddish wax. 

461. Pyro-phosphoric acid. Mr. Clark 
of Glasgow remarked that common phos¬ 
phoric acid is, by heat, converted into a 

substance, which, though unchanged in its constituents or in their com¬ 
bining proportions, exhibits properties of an essentially different kind; this 
new acid he called Pyro-phosphoric * acid. 

Phosphoric acid produces with the oxide of silver a yellow salt, and 
renders a solution of albumen turbid. Pyro-phosphoric acid produces 
with the same oxide a white salt, and does not destroy the transparency 
of albumen. Pyrorphosphoric is less energetic; it has less saturating 
power, and is separated from its combinations by phosphoric acid. And 
yet the only visible effect of heat on phosphoric acid is to expel water, 
which, we should infer, would render the acid more powerful, rather than 
diminish its energies. 

462. Phosphorous acid. It was ascertained by Lavoisier, that 
the slow and rapid combustion of phosphorus produced two 
distinct acids, the phosphorous and the phosphoric. At a 
high temperature, phosphorus, whether burning in common 
air or in oxygen gas, unites with its highest proportion 
of oxygen (two equivalents = 16,) and produces phosphoric acid ; 
at a common temperature it unites with but one equivalent of ox¬ 
ygen -( = 8') and forms phosphorous acid. When sticks of phos¬ 
phorus are exposed to the air in a glass funnel, placed in the 
mouth of a bottle containing a little water, it suffers a slow com- 


Fig. 85. 



* From the Greek pur fire, added to phosphoric. 


460. Decomposition of phosphoric acid . 

461. Discovery of pyro-phosphoric acid. Difference in the properties 
of phosphoric and pyro-phosphoric acids. 

462. Different products of the slow and rapid combustion of phos, 
phorus. 










204 


INORGANIC CHEMISTRY - . 


bustion, phosphorus uniting with oxygen, white fumes appear, 
which being heavier than the air sink into the bottle and are con¬ 
densed by the liquid, one part of phosphorus, being now in¬ 
creased by the oxygen and water combined, produces three 
parts of phosphorous acid. This product, which was formerly 
supposed to be pure phosphorous acid, is now found to contain 
some phosphoric acid, which fact, probably, is owing to the 
union of the phosphorous acid with a new supply of oxygen 
from water. 

463. Sir Humphrey Davy first obtained pure phosphorous acid, by sub¬ 
liming phosphorus through the perchloride of mercury (corrosive subli¬ 
mate.) The corrosive sublimate is put into a glass tube, connected at 
one end with a small receiver (which is to be kept cool) and at the other 
with a small tube containing phosphorus; as heat is applied to the phos¬ 
phorus, it rises in vapor, comes in contact with the corrosive sublimate, 
which it decomposes by combining with its chlorine, and passes into the 
receiver in the form of a limpid fluid, which is the chloride of phosphorus. 
This, on being mixed with water, decomposes it; the chlorine unites 
with the hydrogen of the water, forming hydrochloric, (muriatic,) acid ; 
while the phosphorus attaches itself to the oxygen, producing phospho¬ 
rous acid. The solution being next evaporated to the consistence of syr¬ 
up, muriatic acid is expelled, and the residue, which is the hydrate of 
jihosphorous acid, becomes solid and crystaline in cooling. 

464. From its tendency to unite with an additional quantity of 
oxygen, phosphorous acid is a powerful deoxidizing agent, and 
precipitates mercury, silver, and gold from their saline combi¬ 
nation in the metallic form. On exposure to the air, or in con¬ 
tact with the nitric acid, it absorbs oxygen, and is converted into 
phosphoric acid. Phosphorous acid combines with salifiable 
bases, forming salts called phosphites; it is acid to the taste, 
and reddens vegetable blue colors. Its odor resembles that of 
garlic. 

465. Hypo-phosphoric acid. Is so named on the supposition that it 
contains a smaller proportion of oxygen than the phosphorous acid. It 
combines with salifiable bases forming neutral salts, called hypo-phos¬ 
phites, which are all remarkably soluble in water. Silliman suggests 
that this acid may be a triple compound of oxygen, hydrogen, and phos¬ 
phorous, or a hydracid , in which case its proper name would be hydro - 
phosphoric acid.* 

466. Oxide of Phosphorus. Phosphorus is usually made 
into small sticks of a few inches in length. As it must be pre¬ 
served in water, it is usually kept in vials of this liquid. After 

* Silliman’s Elements, Vol. 1. p. 429. 


463. Mode of procuring pure phosphorous acid. 

464. Properties of phosphorous acid. Phosphites. 

465. Origin of the name hypo-phosphoric acid. Its salts. Silliman’s 
suggestion respecting- its composition. 

466. Formation of the white oxide of phosphorus. Red oxide. 




PHOSPHOROUS ACID. 


205 


being for sometime exposed to the action of water, it becomes 
encrusted with a whitish substance, which is called the white 
oxide of phosphorus. The red colored residue which appears 
after the combustion of phosphorus, is called the red oxide of 
phosphorus. Thenard considers these two oxides identical, ex¬ 
cept that the white oxide is in the hydrated state. 

Compounds of Phosphorus and Chlorine . 

467. There are two definite compounds of phosphorus. One 
discovered by Davy, and called the per-chloride , and the other 
discovered by Gay Lussac and Thenard, and called proto-chlo - 
ride. Their component parts and chemical equivalents are as 
follows. 

Proto-chloride of Phos. 1 Phos. 12 added to 1 Ohio. 36 = 48. 
Per-chloride of Phos. 1 Phos. 12 added to 2 Ohio. 72 = 84. 

468. The Proto-chloride of phosphorus may be obtained by 
passing the vapor of phosphorus over corrosive sublimate (per- 
chloride of mercury,) in a heated glass tube ; the corrosive sub¬ 
limate yields one proportion of chlorine to the phosphorus and 
becomes calomel, or the proto-chloride of mercury ; the phospho¬ 
rus being now changed to the proto-chloride of phosphorus. 
This is a volatile transparent liquid, very caustic, and heavier 
than water. It decomposes rapidly in water in which case a so¬ 
lution of muriatic, (hydro-chloric,) and phosphorus acids is the 
result. Its vapor is combustible. 

469. The Per-chloride of phosphorus , sometimes called the bi¬ 
chloride and deuto-chloride is formed when dry phosphorus is 
burned in chlorine gas. 

467. Discovery and composition of the proto-chloride and per-chloride 
of phosphorus. 

468. Mode of obtaining the proto-chloride of phosphorus. 

469. .How is the per-chloride formed ? Properties, &c. 

18* 




206 


INORGANIC CHEMISTRY. 


The figure represents a tubulated glass 
bottle containing chlorine gas, into which 
some phosphorus being introduced, it 
burns spontaneously, throwing off bril¬ 
liant jets of fire, and giving a pale white 
light. The bladder fastened to the tubu- 
lure is to give space for the expansion of 
the gas by heat, which, as the bottle is 
air tight, might otherwise, cause it to 
break. 

The white, solid, pulverulent substance 
which collects on the inside of the bottle 
is the per-chloride of phosphorus. It 
crystalizes in transparent prisms ; is vol¬ 
atile at a heat less than 212° ; decomposes 
water rapidly, forming with its elements, 
hydro-chloric and phosphoric acids. Some 
chemists regard the chlorides of phospho¬ 
rus as acids, to which they give the name 
of chloro-phosphorous for the proto-chlo¬ 
ride, and chloro-phosphoric for the per- 
chloride. When the per-chloride of phosphorus is heated with about one 
seventh of phosphorus, it passes to the state of proto-chloride. 

Phosphorus with Bromine and Iodine. 

470. Phosphorus unites with bromine and iodine, forming compounds 
which are termed bromides and iodides of phosphorus , but they are in the 
present state of science little understood. 

Compounds of Phosphorus with Hydrogen. 

471. There are two compounds of phosphorus and hydro¬ 
gen, viz. 

Proto-phosphurelted Hydrogen , 2 Hyd. 2 added *to 1 Plios. 
12 = 14. 

Per-phosphuretted Hydrogen , 1 Hyd. 1 added to 1 Phos. 
12 = 13. 

As in the chemical nomenclature, binary* compounds of substances of 
the electro-negative class, which are not acid, are designated by the 
termination ide, as oxide, chloride, bromide , &c., so binary combinations 
of the electro-positive class, which are not of a metallic nature,are distin¬ 
guished by the termination nrct, as phosphuret, carburet, sulphuret, & c. 
When the compound is gaseous , the termination urctted is used, as carbu- 
rettcd hydrogen , sulphuretted hydrogen , &c. 

* A binary compound is one which consists of no more than two 
elements. 

470. Bromides and iodides of phosphorus. 

471. Composition of two compounds of phosphorus and hydrogen. 
The terminations in ide, uret, &c. 





PHOSPHORUS WITH HYDROGEN. 


207 


472. Proto-phosphuretted Hydrogen is sometimes called the bi-hydruret 
of Phosphorus , and liydro-phosphoric gas. It was discovered by Sir 
Humphrey Davy in 1812. It may be obtained when the solid hydrated 
phosphorous acid is heated in a close vessel. It is a colorless gas, with 
a disagreeable odor. It does not take fire spontaneously in the atmos¬ 
phere, as phosphuretted hydrogen does; but when mixed with atmos¬ 
pheric air, or pure oxygen, it detonates violently with the electric spark, 
or when heated to 300“ F., it imflames spontaneously in chlorine gas. 

473. Per-phosphuretted Hydrogen, (called also the Hydruret 
of Phosphorus ,) may be obtained by boiling phosphorus in a 
small retort, with a hot solution of potash, which should entire¬ 
ly fill the vessel, and the beak of the retort should be made to 
dip into a vessel filled with the same solution. . The gas, as it 

is extricated, grad- 
Fig. 87. ually expels the li¬ 

quid from the 
neck, and inflames 
when allowed to 
escape into the 
air ; or it may be 
collected under a 
bell glass, also 
filled with the 
same alkaline so¬ 
lution. One pe¬ 
culiar property of 
this gas is, that of 
spontaneously in¬ 
flaming on mixture with common air or oxygen gas. This com- 
. bustion is accompanied w T ith a beautiful appearance. After the 
explosion, circular, horizontal rings, or coronas, of dense white 
smoke rise in the air, which increase in diameter, and become 
fainter as they ascend.* 

474. Per-phosphuretted hydrogen is decomposed by heat, 
electricity, and the vapor of sulphur. In the latter case, it be¬ 
comes sulphuretted hydrogen. It is supposed that many of those 
fires which are seen at night around burying grounds, and other 

* Some care'is necessary in conducting this experiment, that as small 
a portion of air as possible shall be included in the retort, since the first 
bubbles of phosphuretted hydrogen gas that are formed, will take fire as 
soon as they come in contact with air in the retort, which will be in 
danger of being broken in the percussion. 



472. Synonymes of proto-phosphuretted hydrogen. Discovery. 
Mode of obtaining it, and its properties. 

473. Mode of obtaining per-phosphuretted hydrogen. 

474. Cause of lights seen at night in certain situations, &c. 




















208 


INORGANIC CHEMISTRY. 


places where animal and vegetable substances are undergoing de¬ 
composition, arise in part from phosphuretted hydrogen.” 
“ Travelling once,” says Silliman, u through a deep valley, in a 
dark night, between Wallingford and Durham, Conn., I was sur¬ 
rounded by multitudes of pale, lambent lights ; these were ev¬ 
ery moment changing their position, and some of them were 
within reach of my whip ; they were yellowish, but not in¬ 
tense.” 

This gas decomposes on exposure to the air, and loses its prop¬ 
erty of inflaming spontaneously after standing for a short time. 
It is lighter than common air ; its specific gravity being 9027. 

475. Phosphuret of Carbon. The combination of phosphorus with 
carbon was first effected by M. Proust, in 1799. It is prepared by add¬ 
ing water to the phosphuret of Calcium (phosphuret of lime) ; the mix¬ 
ture is suffered to stand till gas ceases to be evolved; muriatic acid in 
excess is then added to the liquid, which is agitated, then filtered, wash¬ 
ed and dried. Phosphuret of carbon, thus formed, is a soft, yellowish 
powder, destitute of smell or taste. It slowly imbibes moisture from the 
air, and then has an acid taste. 


LECTURE XX. 

SULPHUR.-SILENIUM. 

SULPHUR. 

476. Sulphur is found as a mineral in various parts of the 
world, especially in the vicinity of volcanoes. The crater of an 
extinct volcano in the island of Java, contains many hundred 
tons of sulphur, and large quantities of it are obtained from Ita¬ 
ly and Sicily. It is generally massive, but sometimes crystal- 
ized in octohedrons. Much of the sulphur of commerce, is ob¬ 
tained by applying heat in close vessels to the natural compounds 
of the metals and sulphur, especially to iron pyrites. The vol¬ 
canic sulphur is probably the result of similar decompositions. 

Sulphur is a brittle solid, of a citron or greenish yellow color, 
inodorous, except when heated by friction or fire, and nearly 
tasteless. It is about twice as heavy as water. It is a very bad 


475. Discovery, preparation, and properties of phosphuret of carbon. 

476. Sulphur found in a natural state. Sulphur of commerce, how 
obtained ? Properties. 




SULPHUR. 


209 


conductor of heat and electricity, and becomes negatively elec* 
trifled when rubbed. 

477. Sulphur fuses at about 216° Fahrenheit; it is fluid between 230° 
and 280° Fahrenheit, and when cast into moulds, forms the common roll 
sulphur, or brimstone. As the temperature rises, it thickens and be¬ 
comes darker colored, till at between 425° and 480°, it is so tenacious that 
the vessel may be inverted without spilling it. At 428°, if poured into 
water, it becomes a plastic mass, and is used for taking impressions of 
medals, &c. Above 480°, it liquefies again, but not so perfectly as at 
248°. At 550°, or 600°, it sublimes rapidly ; indeed, a slow evaporation 
commences below the freezing point. The vapor condenses on cold sur¬ 
faces in the form of a crystaline powder, called floxocrs of sulphur. By 
this sublimation, it is cleansed from such impurities as are fixed or less 
volatile than itself; but if the air be not perfectly excluded, a portion of 
the sulphur will be oxidized, forming sulphurous acid, which will give a 
sour taste to the sublimed sulphur. This impurity may be removed by 
washing with water. Sulphur may be crystalized by fusing several 
pounds of it in a large crucible, and allowing it to cool slowly. When 
a crust has formed upon the upper surface, it is to be peforated in two 
places by a hot iron rod, and the sulphur which remains melted, is to be 
poured out. If a sufficient quantity of sulphur has been used and the 
cooling very slow, octahedral crystals of sulphur will be found lining the 
crucible ; otherwise the crystalization will be irregular and confused. 

478. Sulphur is soluble in alcohol, provided the two bodies be brought 
together in the state of vapor ; from this solution, water throws down 
the sulphur as a white hydrate. This white hydrate is called “ milk of 
sulphur.” It is formed when the vapors of water and sulphur are brought 
together; and in many cases of the precipitation of sulphur from solu¬ 
tions of its compounds. It is the only combination of sulphur with wa¬ 
ter, the former being quite insoluble in the latter. 

479. Sulphur takes fire on being heated above 300° Fahren¬ 
heit in the open air ; it burns with a blue flame, and if the air be 
quite dry, produces sulphurous acid gas; if moisture be present, 
some sulphuric acid is formed also. In pure oxygen gas, the 
combination is far more rapid and brilliant; but the product is 
sulphurous acid in this case also. 

.Sulphur has numerous and important uses in medicine. Mix¬ 
ed with charcoal and salt-petre, it forms gun-powder, the explo¬ 
sive property of which is owing to the sudden change of solids 
into gases. It is used for fire matches, for copying medals, and 
furnishes beautiful crystals for ornamental purposes. With iron 
filings, it is use.d as a cement. 


477. Affected by heat. Flowers of sulphur. Crystalized sulphur. 

478. Sulphur with alcohol. Hydrate of sulphur. 

479. Product of the combustion of sulphur. Uses of Sulphur. Ex¬ 
periment showing the effect of ignited sulphurous vapor upon iron wire, 
&c. 




210 


INORGANIC CHEMISTRY. 



Ex. If a gun-barrel, heated 
to a red heat, have a piece of 
, sulphur placed in one end of it, 
i the jet of ignited sulphurous 
vapor will burn iron wire, as if 
) ignited in oxygen gas ; and the 
iron will fall in the form of 
fused globules; these are the 
proto-sulphurets of iron. Hy¬ 
drate of potassa exposed to the 
jet, fuses into a sulphuret of fine 
red color*. Combined with ox¬ 
ygen in the form of sulphurous and sulphuric acids, sulphur is used in 
the arts of bleaching and dyeing. 

480. Compounds of sulphur and oxygen. Of these there are 
four, all of them being acids. 

1. Hyposulphurous acid , 1 Sulp. 16 added to 1 ox. , 8=24. 

2. Sulphurous acid , 1 Sul. 16 “ 2 ox. 16=32. 

3. Hyposulphuric acid, 2 Sul. 32 u 5 ox. 40=72. 

4. Sulphuric acid , 1 Sul. 16 u 3 ox. 24=40. 

481. Hyposulphurous acid. This acid is only known in combination 
with bases, forming salts called hyposulphites. On adding a stronger acid, 
to liberate the hyposulphurous acid, the latter is immediately resolved 
into sulphurous acid and sulphur. The hyposulphites may be formed by 
digesting sulphur in the solutions of sulphites, in which case the addi¬ 
tional dose of sulphur is taken up, and a hyposulphite formed —or, by 
passing sulphurous acid gas into the solutions of hydrosulphurets, when 
half the oxygen of the sulphurous acid goes to the hydrogen of the sul¬ 
phuretted hydrogen, forming water, while the sulphur of the sulphuret¬ 
ted hydrogen, and of the sulphurous acid, combines with the remaining 
oxygen, to form hyposulphurous acid. The hyposulphites are of no use 
in the arts ; their most interesting property, is, that their solutions dis¬ 
solve large quantities of chloride of silver, giving intensely sweet com¬ 
pounds. 

Sulphurous Acid Gas . 


482. This is always the principal product of the combustion of 
sulphur in air or oxygen gas, and is the sole product when moist¬ 
ure is not present. But the best mode of obtaining this gas, is 
by depriving sulphuric acid of a portion of its oxygen. This 
can be done by the agency of many oxidable substances ; chips 
of wood, straw, cork, oil, and other vegetable matters effect it 

* Dr. Hare. 


480. Names and composition of the compounds of sulphur and oxy- 
gen. 

481. Is this acid ever obtained in a separate form ? Effect of decom¬ 
posing the hyposulphites. How may these salts be formed ? Their 
use, &c. 

482. How is sulphurous acid gas obtained ? Reduction of sulphuric 
acid, to sulphurous acid, by heating it with mercury. 



SULPHUROUS ACJD GAS. 


211 


by the aid of heat, their carbon and hydrogen taking oxygen 
from the sulphuric acid. Most of the metals likewise decom¬ 
pose sulphuric acid, becoming oxidized at its expense. The 
best metals for this purpose, are copper and quicksilver. 

The experiment is performed by putting two parts by weight of mer¬ 
cury, and three of strong sulphuric acid, into a glass retort, and apply¬ 
ing the heat of a lamp ; the beak of the retort being under the mercury 
of a pneumatic trough. The peroxide of mercury is formed, and unites 
with some of the undecomposed acid, forming persulphate of mercury, 
which remains in the retort; while the sulphurous acid gas escapes with 
effervescence, and is to be collected under a bell glass in the usual man¬ 
ner. 

484. Sulphurous acid gas is transparent and colorless. Its 
specific gravity is 2.22, (being just twice that of oxygen,) it is 
less elastic than any other gas ; being condensed into a liquid by 
intense cold, or by a pressure of one additional atmosphere. Its 
pungent and suffocating odor, distinguishes it from all other gas¬ 
es, and is generally known, being the odor which always arises 
during the combustion of sulphur. When pure, it cannot pass 
into the lungs, owing to the spasmodic contraction of the glottis 
which it causes. And if inhaled in mixture with air, if excites 
coughing and is injurious to the lungs; it is fatal to animals con¬ 
fined in it. It is incombustible, and extinguishes burning bodies. 
It has a great affinity for water, which, if freed, by boiling, from 
other gases, will absorb 33 times its bulk of sulphurous acid gas, 
at the medium temperature and pressure of the atmosphere. 
The solution thus formed, has the odor and other properties of 
the gas itself, and may be substituted for it in many operations. 
It must, however, be kept in closely stopped bottles ; for, on ex¬ 
posure to the air, it rapidly absorbs oxygen, and is converted 
into sulphuric acid. 

485. Its strong affinity for oxygen is the cause of many of the phenomena 
which take place by the agency of sulphurous acid. Yet affinity is only 
evident when water is present; thus sulphurous acid and oxygen gases, 
both perfectly dry, may remain mixed for any length of time without 
change; but on the admission of water or its vapor, combination rapidly 
ensues. Nitric acid is deprived of oxygen by sulphurous acid, and is 
converted into deutoxide of nitrogen ; solutions of the salts of peroxide 
of iron, are changed by it into salts of the protoxide. Peroxide of man¬ 
ganese, by the action of sulphurous acid, is reduced to the protoxide, 
which combines with the resulting sulphuric acid, and forms a sulphate ; 
and by this re-agent, the oxides of gold, platinum, and others the least 
oxidable metals, are precipitated from their solutions, and reduced to the 
metallic state. Hence sulphurous acid is a powerful deoxidizing agent. 

This gas and its solution in water, possess the property 
of bleaching, and are used for that purpose to some extent; thus 


484. Properties of sulphurous acid gas. Its affinity for water. 

485. Affinity for oxygen. 



212 


INORGANIC CHEMISTRY. 


straw bonnets are bleached by the fumes ot burning sulphur$ 
and a red rose, or dahlia held in the same fumes, or dipped in 
aqueous sulphurous acid, will become white, except where por¬ 
tions have been protected by folds in the leaves. But the bleach¬ 
ing is not permanent, the coloring principle being only combined 
with sulphurous acid,—not destroyed. Consequently, the color 
returns when, by exposure to the air, the gaseous acid has been 
dissipated ! the stronger acids also will restore the color ; and the 
alkalies, by neutralizing the sulphurous acid, produce the same 
effect. 

Sulphurous acid liquefied by cold or by pressure, is ex¬ 
ceedingly volatile, and, by its evaporation, produces cold enough 
to freeze mercury, and to liquefy some other gases. This gas is 
not decomposed by heat alone ; but is deprived of oxygen, when 
brought in contact with hydrogen, potassium, and several other 
of the most oxidable substances, at a red heat. This acid com¬ 
bines with the salifiable bases; and the salts thus formed, are 
called sulphites. 

486. Hijposulphuric Acid is formed when sulphurous acid is passed 
into water, in which peroxide of manganese is kept suspended. 

This acid is of no use in the arts, nor in the laboratory. Its salts are 
generally soluble, even those of the bases with which sulphuric acid 
would form insoluble salts. By some Chemists, this compound is re¬ 
garded, not as a distinct acid, but as a compound of sulphuric and sul¬ 
phurous acids. 

487. Sulphuric Acid. This is the strongest acid, commonly 
known as oil of vitriol. It has an oily consistency, and is some¬ 
times obtained from green copperas , or green vitriol; whence the 
name. It may be here remarked, that several of the salts of 
this acid have obtained the name of vitriol , from their glassy ap¬ 
pearance ; as green vitriol , which is a sulphate of protoxide of 
copper ; white vitriol , sulphate of the oxide of zink. 

488. Pure sulphuric acid is transparent and colorless : it is 
not fluid as water, but flows more like oil, when poured out; its 
taste is intensely sour, even when largely diluted ; and its spe¬ 
cific gravity, when most- concentrated, is nearly 1.85. It is one 
of the strongest acids known, combining with all the salifiable 
bodies, and even taking them away from almost all other acids, 
by its superior affinity. It oxidizes many of the metals, and 
then combines with the. oxides; in some cases the acid must be 
strong, the metal being oxidized at its expense, as in the prepara- 


485. Bleaching property. Effect of cold or pressure upon this acid. 
Decomposition. Compounds. 

486. Formation of hyposulphuric acid. 

487. Salts of this acid, &c. Origin of the name, oil of vitriol, &c. 

488. Properties of sulphuric acid, &c. Its affinity for water. 



SULPHURIC ACID. 


213 


lion of sulphurous acid gas, in other cases, the acid must be 
dilute, the water furnishing oxygen to the metal, and hydrogen 
gas being evolved. 

Sulphuric acid has a very great affinity for water, uniting with 
it in every proportion. This combination is attended with con¬ 
densation, on which account great heat is evolved ; the increase 
of temperature sometimes exceeds 212°. Snow is melted by 
mixture with this acid, and if the proportions be rightly adjust¬ 
ed, great decrease of temperature is observed. This acid at¬ 
tracts watery vapor rapidly fiom the atmosphere, and is there¬ 
fore used to promote evaporation by means of the air pump. It 
is said that, in the course of a month, sulphuric acid will absorb 
water enough from the air, to double its weight ; and that the 
affinity is not satisfied till the weight of the acid is augmented six 
fold. By jreason of this affinity, sulphuric acid corrodes organic 
substances powerfully, causing their oxygen and hydrogen to 
unite and form water, while their carbon remains. It is on this 
account that this acid often appears deeply colored ; the color 
arising from the carbon of minute portions of vegetable water 
which have fallen in and been decomposed. Wood maybe stain¬ 
ed black by washing it with very dilute sulphuric acid, and then 
warming it so that the water may be dissipated and the action of 
the acid favored by the heat. Water acidulated with this acid, 
may also be used as a sympathetic ink, letters formed with it 
being rendered apparent on warming the paper. 

Sulphuric acid dissolves minute portions of charcoal and sul¬ 
phur. The former communicates to it a blue green, or brown 
tinge and the latter a pink or brown ; the color depending in each 
case on Idle quantity dissolved. 

489. The strength of this acid may be judged of by its specif¬ 
ic gravity. Or, it may be accurately determined by ascertaining 
the exact quantity of pure carbonate of soda required to neutral¬ 
ize a known quantity of the acid. 

Ordinary sulphuric acid freezes at 15°, F. below zero. Its 
boiling point is 620°, F. 

491. The strongest sulphuric acid which can be prepared by the or¬ 
dinary method is a hydrate, still containing an atom of water to an atom 
of acid. But it can be procured perfectly anhydrous by means of fuming 
sulphuric acid. 

This^ substance is the product of a very old process, still in use at 
Northausen in Germany. Green vitriol (protosulphate of iron,) is heat- 

489. How to test the strength of this acid. Freezing and boiling 
points. 

491. Anhydrous sulphuric acid. How procured? Turning sul¬ 
phuric acid, in what manner produced ? Properties of fuming sul¬ 
phuric acid. Separation of the hydrous acid. Properties of the anhy¬ 
drous acid. 


19 




214 


INORGANIC CHEMISTRY. 


ed till six of its seven proportionals of water of crystalization are ex¬ 
pelled, and the salt becomes a powder of a dirty white color; it is then 
subjected to distillation at a red heat. Part of the sulphuric acid passes 
over and is collected in the receiver ; but the other part undergoes de¬ 
composition, being resolved by the heat into sulphurous acid and oxy¬ 
gen. The former gas, with part of the oxygen is evolved ; the remain¬ 
der of the oxygen combines with the protoxide of iron, which thus be¬ 
comes peroxide and remains in the retort. 

The acid thus procured is dense and oily, and has a brownish color. 
It is heavier than the common sulphuric acid and emits dense white 
fumes when exposed to air, especially if the atmosphere be moist. It 
consists of real acid and water, in such proportions that it may be con¬ 
sidered a compound of one equivalent of anhydrous, and one of hydrat¬ 
ed sulphuric acid. The anhydrous acid being volatile below 122°, while 
the hydrous requires a temperature of 620°, it is easy to separate them 
by distillation at a very gentle heat; but the vessels must for this pur¬ 
pose be perfectly tight. 

The anhydrous acid passes over as a perfectly transparent and colorless 
vapor and is condensed in the coal receiver, into a white and crystaline, 
or a transparent, glassy solid, according to the rapidity of cooling.—It is 
liquid in summer, unless artificially cooled.—It has a greedy attraction 
for water, combining with the moisture of the air and forming dense 
white fumes if exposed ; and if thrown into water it evolves great heat, 
causing a hissing and boiling like red hot iron. 

492. Sulphuric acid occurs abundantly in nature in combin¬ 
ation with earths, forming salts, of which the most plentiful are 
sulphate of lime (gypsum or plaster of Paris,) and sulphate of 
baryta (heavy spar;) but it is seen seldom in an uncombined 
state, except near volcanoes. A large deposit of sulphur in Ja¬ 
va, (If 476,) is the source of a stream of diluted acid, which in 
the rainy season flows down the mountain, destroying the vege¬ 
tation along its banks ; and Professor Eaton mentions a pond 
near Rochester N. Y. the waters of which, especially in a dry 
season contain some quantity of this acid. The latter is, per¬ 
haps, the only case on record of the receiver of this acid inde¬ 
pendently of volcanoes. 

This acid, or any of its soluble salts can always be detected in so¬ 
lution, by the addition of solution of baryta or muriate of baryta when 
a heavy white precipitate will be formed, which is insoluble in acids and 
alkalies. 

493. Sulphate of Ammonia. This salt is employed in chemical manu¬ 
facturing establishments, for obtaining muriate of ammonia. For this 
purpose, it is obtained by lixiviation from the soot of coal; or by apply¬ 
ing heat to a mixture of gypsum (sulphate of lime,) and an impure car¬ 
bonate of ammonia, which is procured by distilling bones and other 
animal matters. It is very soluble in water; crystalizes in long flattened 
hexahedral prisms; and is sublimated by heat, part of it being decom¬ 
posed at the-same time. 


492. Existence of sulphuric acid in nature. Tests of sulphuric acid. 

493. Composition, &c. of sulphate of ammonia. 



SULPHATE OF AMMONIA. 


215 


Combinations of Sulphur and Hydrogen. 


494. These two bodies combine in two proportions, and 
form. 


Hydro-sulphuric acid, or } Sulphur. Hydrogen. 

Sulphuretted Hydrogen, 5 containing one equiv. added to one equiv. 
Bisulphuretted Hydrogen, two added to one 


495. Sulphuretted Hydrogen* is a gas, formed by heating sul¬ 
phur in hydrogen, or by bringing sulphur and hydrogen together 
in a nascent state; 


Let a portion of sulphur be put into a ves¬ 
sel, to the neck of which is fitted a bag of hy¬ 
drogen gas ; as the sulphur is heated it vola- 
talizes, and its vapor rising unites with the 
hydrogen to form sulphuretted hydrogen. 
The gas may be collected over water. 

496. Sulphuretted hydrogen is colorless ; 
its specific gravity is 1.18, a little more than 
that of atmospheric air; it requires a pressure 
of 17 atmospheres to reduce it to the liquid 
state. Its odor is fetid, as may be perceived 
in putrid eggs, or the washing of a gun-barrel. 
Its taste also is unpleasant, of which the water 
of sulphuretted springs is an example. This 
gas is poisonous even when mixed with a 
large quantity of air. It does not support com¬ 
bustion, but is itself combustible, burning with a pale blue flame; 
the products of the combustion are water and sulphurous acid. 
It also explodes on being ignited when mixed with air or oxygen, 
furnishing the same products. 

497. Potassium, tin, and some other metals decompose this gas when 
heated in it, uniting with the sulphur and liberating the hydrogen. 
Electric sparks, or a platinum wire ignited by galvanism, will also de¬ 
compose sulphuretted hydrogen. In these experiments, the hydrogen 
evolved is equal' in bulk to the sulphuretted hydrogen decomposed. 

Sulphuretted hydrogen and sulphurous acid, mutually decompose each 
other, the oxygen of the one uniting with the hydrogen of the other ; and 


Fig. 89. 



* Sometimes called hydro-thionie acid, from the Greek hudor y water, 
and theion , sulphur. 


494. Combinations of sulphur with hydrogen. 

495- Nature, and formation of sulphuretted hydrogen. 
496. Properties. 

497 . Decomposition. Absorption by water. 





216 


INORGANIC CHEMISTRY. 


the sulphur of both is deposited. Nitric acid poured into a phial of this 
gas, deomposes it by furnishing oxygen ; sulphur is deposited, and water, 
and deutoxide of nitrogen are formed. Water at 60° F., if freed by boil¬ 
ing, from other gases, will absorb about its Own bulk of this gas, and 
afford a solution which has the odor, taste, and chemical action of the 
gas itself, and may therefore be used as a test. This solution is very 
easily decomposed by substances which yield oxygen, and even by expo¬ 
sure to air ; the oxygen uniting to the hydrogen of the sulphuretted hy¬ 
drogen, and the sulphur being deposited. This cause accounts for the 
constant deposition of sulphur from the water of sulphuretted springs. 

498. Sulphuretted hydrogen is an important test for metals, in 
solutions of which, it produces precipitates of metallic sulphur- 
ets ; these precipitates are of different colors, by which we are 
enabled to ascertain what metal is present. The gas acts also on 
many insoluble metallic compounds ; thus, white paint, (carbon¬ 
ate of lead,) and the cosmetic pearl white, (oxide of bismuth,) 
are rendered black, or dark brown by this gas, ow ing to the form¬ 
ation of the black sulphurets of lead, and of bismuth. At sul¬ 
phuretted springs, some ludicrous changes of complexion have 
occasionally happened to ladies beautified with pearl w hite. The 
blackening of white lead, (carbonate of lead,) and sugar of lead, 

(or the acetate of 
lead,) make these 
substances deli¬ 
cate tests for the 
presence of sul¬ 
phuretted hydro¬ 
gen. 

The acetate of 
lead, in solution, is 
colorless, but let a 
drawing be made 
with it in this state, 
and then exposed 
to the action of a 
stream* of sulphu¬ 
retted hydrogen 
gas, the lines will 
become black, as if 
made with a lead 
pencil. 

This gas also tarnishes gold and silver, its sulphur combining 
with those metals to form sulphurets. Chlorine may be used 
to purify an atmosphere contaminated with sulphuretted hy¬ 
drogen. 

* This stream of gas is invisible, though represented in the figure. 


Fig. 90. 



498. Action on metals, and metallic compounds. 





SULPHURIC ACID. 


217 


499. Sulphuretted hydrogen is properly called hydro-sulphuric acid , 
(see § 337,) for it reddens litmus paper, and combines with the fixed 
alkalies, and with ammonia; its relations to the metalic oxides being 
perfectly analogous to those of the other hydracids. Its salts are prop¬ 
erly hydro-sulphates though usually termed hydrosulphuretts. They are 
decomposed by all the strong acids, sulphuretted hydrogen gas escaping 
with effervescence. They are decomposed by chlorine, bromine, and 
iodine, producing muriates, hydrobromates, and hydriodates ; and by ex¬ 
posure to air, by which, first the hydrogen, and afterwards the sulphur, 
is oxidized, and the solution, originally colorless, becomes first a yellow 
sulphuretted hydrosulphuret, and ultimately a hyposulphite. 

With the alkalies, sulphuretted hydrogen combines in two proportions, 
forming a hydrosulphate, and a bi-hydrosulphate. These salts are solu¬ 
ble, deliquescent, and crystalizable. They have the odor of sulphuretted 
hydrogen, give a stain to animal substances, and are sometimes employ¬ 
ed for dyeing the hair. Their solutions act on flint glass bottles, render¬ 
ing them black and opake ; owing to mutual decomposition of sulphuret¬ 
ted hydrogen, and the oxide of lead contained in the glass, which results 
in the formation of a black sulphuret of lead. The only two in use, as 
re-agents, are those of ammonia and potassa. The Hydrosulphate of 
Ammonia is a very volatile body, and has an exceedingly offensive smell, 
in which the odors of ammonia and of sulphuretted hydrogen, are both 
perceptible. Its solution is transparent, and generally yellow. It is used 
as a test in metallic solutions, where sulphuretted hydrogen alone does 
not cause a precipitation. Its solution emits white fumes. It was dis¬ 
covered by Boyle, and was formerly called u BoyVs fuming liquor." It 
may be formed directly, by mixing sulphuretted hydrogen, and ammoni- 
cal gases in dry glass vessels cooled with ice ; the salt is deposited in 
crystals. 

500. Bi-sulphuretted hydrogen has also the properties of a weak 
acid, and its salts are called hydroguretted sulphurets 1 or sulphuret¬ 
ted hydro-sulphates. They are formed when solutions of hydro- 
sulphurets are exposed to the air ; or when an alkali is boiled in 
water, with excess of sulphur ; or by digesting sulphur in solu¬ 
tions of sulphurets. The solutions are yellow ; they are grad¬ 
ually converted into hyposulphites, by absorbing oxygen from 
the air, or more quickly by sulphurous acid ; and are decomposed 
by the addition of a stronger acid. It is a yellow, viscid, semi¬ 
fluid, heavier than water, and having, in a lower degree, the same 
odor and taste as sulphuretted hydrogen. Bi-sulphuretted hy¬ 
drogen contains 2 atoms of sulphur, aud sulphuretted hydrogen 1 
of sulphur to l .atom of hydrogen. Thus the word bi-sulphuret¬ 
ted signifies twice sulphuretted. 

501. Chloride of sulphur. This is a compound of one equivalent of 


499. Proper name for sulphuretted hydrogen. Its acid properties. Its 
salts. Decomposition of these salts. Combinations with alkalies. With 
hydro-sulphate of ammonia. 

500. Composition, &c., of bi-sulphuretted hydrogen. Formation of its 
salts. Formation of bi-sulphuretted hydrogen. Properties. 

501. Constitution, properties, &c. of chloride, bromide and iodide of 
sulphur. 


19 * 




218 


INORGANIC CHEMISTRY. 


each constituent, and is formed, directly, by passing chlorine over flow¬ 
ers of sulphur gently heated. It is a volatile liquid of a red color, when 
seen in mass, but greenish yellow, when a thin stratum is looked through. 
It decomposes water rapidly, the chlorine taking the hydrogen; at the 
game time sulphur is deposited, and sulphurous and sulphuric acids are 
formed. Its vapor also decomposes the moisture of the air, giving fumes 
which affect the eyes powerfully, and which probably consist of the 
same acid products. 

Bromide of sulphur is a red, volatile, oily liquid, which decomposes 
water with great violence, and which is obtained by the direct action of 
bromine on sulphur. It is decomposed by chlorine, and chloride of sul¬ 
phur is formed. 

Iodide of sulphur is likewise formed by direct action of its elements, 
aided by heat. It is a dark solid and is decomposed by heat. 

Compound af Sulphur and Carbon . 

502. There is, only oqe known compound of sulphur and car¬ 
bon. It contains two equivalents of sulphur, and one of car¬ 
bon, and is therefore a Bi-sulphuret of carbon. This substance, 
otherwise called alcohol of sulphur , is obtained by passing vapor 
of sulphur over charcoal, heated red hot in a porcelain tube. It 
is to be conducted into a vessel of water, at the bottom of which 
as it is heavier than water, it collects. It is a transparent liquid, 
of great refracting power, an acrid and pungent taste, and dis¬ 
gusting odor. It boils at 10 & Fahrenheit, and evaporates so 
rapidly at common temperatures, as to cause great cold. It burns 
with a blue flame, producing sulphurous und carbonic acid gases. 

It is converted by nitro-muriatic acid, into a substance resembling 
camphor, but it is scarcely affected by the other acids ; alkalies unite 
with it slowly, forming carho-sulphurets. It dissolves sulphur, phospho¬ 
rus, and iodine, the last giving a pink solution. Chlorine decomposes 
it, and unites with the sulphur. It will not mix with water, but dissolves 
readily in alcohol and ether, from which solution water precipitates it. 
When an alkali is put into the alcoholic solution, it becomes neutralized, 
owing to the formation of a new acid, which has been called hydroxanthic 
acid, from the yellow color of its salts. This latter acid appears to con¬ 
sist of. carbon, sulphur, and hydrogen, the hydrogen and an additional 
dose of carbon, being derived from the alcohol. 

SELENIUM. 

503. Selenium was discovered by Berzelius in 1818. It was 
observed, in a manufacture of sulphuric acid at Fahlun, in Swe¬ 
den, that the sulphur, after sublimation, deposited a reddish mass. 

502. Compounds of sulphur and carbon. Mode of obtaining bi-sul¬ 
phuret of carbon. Properties. Combustion, &c. Hydroxanthic acid. 

503. Discovery of selenium. Origin of the name. With what sub¬ 
stances united, and where found. Why not classed among the metals ? 
Properties of selenium. 



SELENIUM AND OXYGEN. 


219 


This was submitted to the examination of the Swedish Chemist, 
who obtained, by analysis, a very minute proportion of an ap¬ 
parently new substance. The remainder of the mass being a 
compound of mercury, tin, arsenic, lead, copper, zink, iron, and 
sulphur. This new substance, Berzelius named selenium , from 
the Greek, selene , the moon, on account of its resemblance to 
tellurium, so called from tejlus , the earth. The substance in 
which the sulphur and selenium were thus found united, was 
iron pyrites, (sulphuret of iron^) from the mines of Fahlun. 
Selenium has since been found in combination with minerals in 
the Hartz mountains and in volcanic products of the Lipari is¬ 
lands, and in pyrites of the isle of Anglesea in England. Se¬ 
lenium was regarded, by its discoverers, as a metal, and is now 
sometimes classed among the metals, but being an imperfect con- 
ducter of heat and electricity, it appears to belong to the class of 
simple non-metallic elements. 

It is solid at qommon temperatures, brittle, opake, and inodor¬ 
ous. It softens on exposure to heat; at 212° Fahrenheit, it be¬ 
gins to liquefy, aud fuses at a temperature a few degrees higher. 
If partly cooled when in this state, it appears like wax, and may 
be drawn out by the fingers, into long, transparent, elastic 
threads, which appear red by transmitted light, but grey, and of 
a metallic brilliancy, when seen by reflected light. At 650° 
Fahrenheit, it volatizes, becoming a yellow vapor. Its vapor, 
suddenly cooled, produces a red powder, resembling the flowers 
of sulphur, except in color. If sublimed in the air, without ta¬ 
king fire, its vapor is red and without odor. But when heated 
in the flame of a lamp, heightened by a current of air from a 
blow pipe, it tinges the flame a light blue color, and emits a 
strong odor, resembling that of decayed horse-radish, in which 
property it resembles tellurium. In many of its properties, se¬ 
lenium resembles sulphur; and in its specific gravity and metal¬ 
lic lustre, it resembles metals. 

Compounds of Selenium and Oxygen. 

504 .Selenic Acid. Selenic acid maybe obtained by dissolving one 
part of selenium, in three parts of nitric acid, and boiling the mixture. 
The selenium decomposes the nitric acid, and a solution of selenic acid 
is formed; this may be evaporated to dryness, and then appears as a 
white mass, which may be sublimed on raising the temperature; the 
color of the vapor resembles that of chlorine. 

Selenic acid has a sour taste, reddens vegetable blues,, and has a strong 
affinity for salifiable bases. It powerfully attracts water, and like sul- 


504. Composition, and mpde of obtaining selenic acid. Properties. 
Selenio-muriatic acid. Selenic acid with metals. Salts of selenic acid. 




220 


INORGANIC CHEMISTRY. 


phuric acid, gives out much heat when mixed with it. "When exposed 
to heat, it volatilizes without any decomposition. When heated with 
muriatic acid, selenious acid and chlorine gas are evolved, and the se. 
lenio-muriatic acid, like the nitro-muriatic, (aqua regia,) dissolves gold- 
Selenic acid also dissolves gold, but not platinum. It dissolves zinc and 
iron, while hydrogen is evolved; in dissolving copper, selenious acid is 
formed. The salts of this acid are called seleniates. 

505. Selenious Acid. When selenium, heated to its boiling point in a 
close vessel, is supplied with a current of oxygen gas, it burns with a 
pale, blueish green flame ; selenious acid sublimes, and if condensed in a 
cool receiver, will form long, striated, prismatic crystals. Its taste is 
sour, and somewhat burning ; it is readily decomposed by substances 
which have a strong affinity for oxygen. Its affinity for water is such, 
that it attracts it from the air. Its salts are called selenites. It was dis¬ 
covered by Berzelius, and being until recently, supposed the only acid 
of selenium, was termed selenic acid. But since an acid compound is 
now known to exist, in which selenium unites with a higher proportion 
of oxygen, the latter must be considered as the true selenic acid. 

506. Oxide of selenium. The composition of this substance is some¬ 
what doubtful, though it is supposed to contain one atom of oxygen and 
one of selenium. It is formed by heating selenium in a close vessel with 
atmospheric air. 

Compounds of Selenium with Chlorine , Bromine , Hydrogen , 
Phosphorus , and Sulphur. 

507. Pi oto-chloride of selenium may be obtained by passing chlorine gas 
over selenium ; it is a liquid of a brown color, heavier than water. It is 
decomposed by water, forming muriatic and selenious acids. Per-chlo¬ 
ride of selenium is obtained by adding chlorine to the proto-chloride. 

The Bromide of Selenium was obtained by Serullas, by causing sele¬ 
nium, in minute portions, to fall upon bromine, combination ensued with 
a disengagement of heat. At the common temperature, it was solid, 
orange colored, and soluble in water. 

Hydro-selenic acid , or Seleniuretted hydrogen is a compound of one 
atom of selenium=40, and one of hydrogen=l, making its equivalent 
41. Its discoverer, Berzelius, found it to be, in many of its properties, 
similar to sulphuretted hydrogen. Silliman suggests, that the noxious 
properties of the latter compound may be often increased, by the pres¬ 
ence of selenium, as sulphur is often contaminated with it. Hydro-se- 
lenic acid may be obtained by dissolving seleniuret of iron in muriatic 
acid. Its solution reddens litmus paper, and gives a brown tint to the 
skin. It is readily decomposed by the action of air and water, and gives 
a red color to moist substances. It acts injuriously on the animal sys¬ 
tem. 

Phosphuret of selenium is obtained by bringing selenium into contact 
with phosphorus, when in a state of fusion. It is inflammable and very 
fusible. Sulphuret of selenium , as obtained by Berzelius, was an orange 


505. Composition and formation of selenious acid. Properties. Salts. 
Discovery and former name. 

506. Composition and formation of the oxide of selenium. 

507. Compounds of selenium with chlorine. Bromide of selenium. 
Hydro-selenic acid. Phosphuret of selenium. Sulphuret of selenium. 



TABULAR VIEW OF CHEMICAL ELEMENTS. 


221 


colored precipitate, formed after conducting sulphuretted hydrogen into 
a solution of selenic acid. 

We have now completed the study of the non-metallic elements , 
with the combinations which they form with each other. The 
following table exhibits them arranged according to the division 
into two classes, which we have adopted, viz., of electro-posi¬ 
tive, and electro-negative elements, and also shows their com¬ 
bining equivalents. These elements exist in the three different 
states of gaseous or ceriform y volatile , and fixed , as represented in 
the table. 

TABLE I. 

508 NON-METALLIC ELEMENTS. 



Electro-Negative. 

Equiv. 

Electro-Positive. 

Equiv. 


Oxygen. . . 

8 



Aeriform. « 



Hydrogen. . 

. . 1 


> 


Nitrogen. 

. . 14 


Chlorine . . 

. 36 




Bromine . . 

. 75 




Iodine . . 

124 



Volatile. -{ 

| Fluorine . . 

10 

Suiphur . . 

. . 16 

' 



Phosphorus . 

. . 12 

1 

t'-’ 


Selenium 

. . 40 


) 


Carbon . . 

. . 6 

Fixed.or j 



Silicon . . 

. . 8 

Solid. } 

1 


Boron . . 

. . 6 


509. The binary compounds of the simple non-metallic ele¬ 
ments are arranged in the following table, under three divisions, 
viz. the Acid , the Alkaline or Basic , and the Neutral. The 
proportions in which their component parts unite, with the equiva¬ 
lent number of each, showing the ratio in which their binary 
compounds will combine with other bodies. 

TABLE II. 


BINARY COMPOUNDS OF THE NON-METALLIC ELEMENTS. 





, - "i ' 

£g.'§ 






j * 



•S 



M ® NEUTRAL. 

sS 


'3 

ACID. 

•«s» 

J BS 

•< o v 

'S 

kf added to 


Electro-Negative . > 


Sq 


1 Chlorine 

1 Oxygen 


j 

Protoxide of Chlorine 

44 

Ditto 

4 Ditto 



Peroxide of Chlorine 

68 

Ditto 

5 Ditto 

Chloric acid 

76 



Ditto 

8 Ditto 

Per-chloric acid 

D2 




508. Repeat the names and equivalents of the Electro-negative ele¬ 
ments, and of the Electro-positive non-metallic elements. 

509. Divisions of the binary compounds as the simple non-metallic 
elements, their equivalents. 







Eqniv, 


222 


INORGANIC CHEMISTRY 


added to 


g. 


ACID. 

Electro-Negative. 



W • 

> U Co 
r, •-» « 
^ «o ft. 

d -< r 

< jc © 

3 ptf ts 

< o « 

N 


NEUTRAL. 


1 Bromine 

5 Oxygen 

Bromic acid 

115 


Ditto 

1 Chlorine 

N, 


Chloride of Bromine 

1 Iodine 

5 Oxygen 

Iodic acid 

1G4 

/ 

1 Hydrogen 

1 Oxygen 

. y 


Water 

1 Ditto 

2 Ditto 



Protoxide of Hydrogen 

1 Ditto 

1 Chlorine 

Hydro-chloric acid 

37 


1 Ditto 

1 Bromine 

Hydro-bromic acid 

76 


1 Ditto 

1 Iodine 

llydro-iodic acid 

125 


1 Ditto 

1 Fluorine 

Hydro-fluoric acid 

11 


1 Nitrogen 

1 Oxygen 



Protoxide of Nitrogen 

1 Ditto 

2 Ditto 

- 


Deutoxide of Nitrogen 

1 Ditto 

3 Ditto 

Hypo-nitrous acid 

38 


1 Ditto 

4 Ditto 

N itrous acid 

46 


1 Ditto 

5 Ditto 

Nitric acid 

54 


1 Ditto 

4 Chlorine 

a 


» Chloride of Nitrogen 

1 Ditto 

3 Iodine 



S fodide of Nitrogen 

1 Ditto 

Bromine 


Amm-u Bromide of Iodine 

1 Ditto 

1 Hydrogen 


onia. 

17 

1 Carbon 

1 Oxygen 



Carbonic oxide 

1 Ditto 

2 Ditto 

Carbonic acid 

22 


2 Ditto 

3 Chlorine 



Perchloride of Carbon 

2 Ditto 

1 Ditto 



Proto-chloride of Car. 

1 Ditto 

2 Hydrogen 



Subcarburetted Hyd. 

2 Ditto 

2 Ditto 



Percarburetted Hyd. 

2 Ditto 

1 Nitrogen 



Cyanogen 

1 Boron 

2 Oxygen 

Boracic acid 

24 


1 Ditto 

2 Chlorine 



Chloride of Boron 

1 Ditto 

Fluorine 



Fluoride of Boron 

1 Silicon 

2 Oxygen 



Oxide of Silicon 

1 Ditto 

Chlorine 



Chloride of Silicon 

1 Ditto 

1 Fluorine 

Fluo-silicic acid gas 

18 


1 Phosphorus 1 Oxygen 

Phosphorous acid 

20 

- 

1 Ditto 

2 Ditto 

Phosphoric acid 

28 


2 Ditto 

J Ditto 

Hypo-phosphorous acid 32 


1 Ditto 

1 Chlorine 



Proto-chloride of Phos. 

1 Ditto 

2 Ditto 



Per-chloride of Phos. 

Ditto 

Bromine 



Bromide of Phos. 

Ditto 

Iodine 



Iodide of Phos. 

1 Ditto 

2 Hydrogen 



l’roto-phosphuretted H. 

1 Ditto 

1 Ditto 



Per-phosphuretted Hy. 

1 Sulphur 

2 Oxygen 

Sulphurous acid 

32 


1 Ditto 

3 Ditto 

Sulphuric acid 

40 


1 Ditto 

1 Ditto 

Hypo-sulphurouS acid 24 


2 Ditto 

5 Ditto 

Hypo-sulphuric acid 

72 


1 Ditto 

1 Hydrogen Sulphuretted Hyd. 

17 


2 Ditto 

1 Ditto 

Bi-sulphuretted Hyd. 

33 


1 Ditto 

1 Chlorine 



Chloride of Sulphur 

Ditto 

Bromine 



Bromide of Sulphur 

Ditto 

Iodine 



Iodide of Sulphur 

Ditto 

Carbon 

Bi-sulphuretof carbon (?) 


1 Selenium 

3 Oxygen 

Selenic acid 

64 

- 

1 Ditto 

2 Ditto 

Selenious acid 

56 


1 Ditto 

1 Ditto 



Oxide of Selenium 

Ditto 

Chlorine 



Chloride of Selenium 

I 1 Ditto 

1 Hydrogen 

Hydro-selenic acid 

41 


Ditto 

Phosphorus 


Fliospliuret of Selen’m 

Ditto 

Sulphur 



Sulphate of Selenium 


Ill 

9 

17 


29 

30 


158 

386 

(?) 


14 

120 

42 

8 

14 

26 


80 


16 

(?) 


48 

84 

(?) 

(?) 

14 

13 



48 

(?) 


METALS. 


223 


METALS. 

OR THE SECOND DIVISION OF ELECTRO¬ 
POSITIVE ELEMENTS. 

LECTURE XXL 

GENERAL OBSERVATIONS UPON THE METALS.-FIRST CLASS OF 

METALS, OR THOSE WHICH FORM ACIDS WITH OXYGEN. 

510. From the 13 simple non-metallic elements we pass to the 
consideration of metals or metallic elements; these are 41 in number. 

The metals vary greatly among themselves in their physical 
properties. Some, as gold and platinum, are the heaviest sub¬ 
stances known ; while others, as sodium and potassium are 
lighter than water. Mercury is liquid at the common tempera¬ 
ture and can be solidified only by cold far below that of the 
freezing point of water ; but .platinum remains solid even under 
the influence of the most intense heat. In their chemical affini¬ 
ties, metals differ greatly. Potassium and sodium have so great 
an attraction for oxygen, that they become oxidized from mere 
exposure fo the air ; while silver and gold can with difficulty be 
made to unite with oxygen. 

511. The distinctive characters of the metals are as follows ; 
they are good conductors of electricity and heat ; the former 
passes through them instantaneously, the latter progressively, 
though rapidly. They are determined to the negative pole in the 
galvanic series, when combined with oxygen, chlorine, iodine, 
bromine, or sulphur ; and their oxides have the same destination, 
when combined with acids ; hence the metals are said to be elec¬ 
tro-positive. They are opake ; they reflect the light powerfully, 
and with a peculiar glitter, termed the metallic lustre. This 
property is retained by the metals when divided into the minu¬ 
test particles. Though good conductors, they are bad radiators 
of heat. They are fusible at different degrees of heat; and when 
melted retain their lustre and opacity. They possess in different 
degrees a peculiar tenacity , which renders them malleable and 
ductile , or capable of being extended under the hammer or drawn 
into a wire. They are capable of combining with oxygen and thus 
forming oxides that bear a metallic appearance ; those oxides, by 
uniting with acids, saturate them and form salts. 

512. Of all substances in nature, none have, perhaps more at- 

510. Number of metals. Variety in the properties of metals. 

511. General characteristics. 

512. Early attention of mankind to this class of bodies. 



224 


INORGANIC CHEMISTRY, 


tracted the attention of mankind than the metals. To the ex¬ 
periments of the alchemists, in their attempts to transmute the 
baser metals into gold and silver, the science of chemistry owes 
its existence. Yet notwithstanding the researches of the alche¬ 
mists, so late as the fifteenth century, only seven metals, appear 
to have been discovered; viz. gold, silver, iron, copper, lead, 
mercury, and tin, with a few ores and combinations with other 
metals. 

513. The metals have been variously classified by different 
writers. Some have arranged them according to their relative 
affinities for oxygen, which vary so much, that while one class 
part with oxygen by the mere application of heat, another class 
retain it so strongly that it requires the greatest power of the 
voltaic pile to effect their disunion. But though the extremes, in 
respect to affinity for oxygen, may widely differ, there are many 
metals included between those which part easily with oxygen 
and those which strongly retain it; and this circumstance ren¬ 
ders it difficult to class them upon this principle. 

It is well for science, that its foundation stands firm, though some of 
the superstructures erected upon it may fall. Though in mental and 
moral science, classification varies with almost every writer, yet truth is 
immutable , and those various classifications are but as so many mirrors 
in which she is exhibited in different lights. The same is true in the 
physical sciences ; one mode of classification brings out in bold relief one 
set of properties, and another mode brings into light other properties, 
which, but for this kind of distinction, might not have been duly ob¬ 
served. 

514. We shall arrange the metals into four classes. 

1st. Those which form acids with .oxygen. 2d. The alkaline 
metals, or those whose oxides are either fixed alkalies or alkaline 
earths. 3d. Earthy metals, or those whose oxides are earths. 
4th. Metals whose oxides are not regarded as earths or alkalies. 

515. The Metals.of the first class , or those which form acids 
with oxygen. These are thirteen in number, as follows, viz. 
arsenic , antimony , Columbian , litanium , chromium , molyhdinum , 
tellurium , tungsten , vanadium , uranium , manganese , cobalt , and tin. 

ARSENIC. 

516. The name is supposed to be derived of the Arabic, arsa- 
nak , signifying strong and deadly qualities. It was noticed in 
combination with sulphur, by the Greek philosopher Dioscorides 

513. Various classifications of metals. 

514. Divisions of metals into four classes. 

515. Metals of the first class. 

516. Derivation of the word arsenic. Discovery. Mode of obtaining 
the metal. Properties. Native state. 




ARSENIC AND OXYGEN. 


225 


under the name of sandarac. In 1773, Brandt discovered it to 
be a distinct metal. The substance usually called arsenic is the 
arsenious acid or white oxide of arsenic. From this, the metal 
may be obtained by mixing it with oil and subliming in a close 
vessel. Arsenic has a metallic lustre, resembling that of polish¬ 
ed steel; it is brittle and granular in its texture. Exposed to 
the air it becomes tarnished, and covered with a blackish sub¬ 
stance, which appears to be a protoxide of arsenic. Thrown 
upon burning coals, arsenic burns with a blue flame, volatilizing 
in the form of white vapors, and with a strong smell of garlic, a 
property which affords a distinguishing character for this metal. 
It is sometimes found pure and native, but it is more commonly 
combined with the ores of other metals, especially iron and co¬ 
balt ; by roasting these ores, the arsenic* which is very volatile, 
vaporizes and condenses in receivers prepared for the purpose. 

517. Two compounds of Arsenic and Oxygen are known to 
exist; their composition and combining proportions, as stated by 
Berzelius and followed by Turner, are as follows : 

Arsenic. Oxygen. 

Arsenious acid, 38 or 1 equiv. 12 or 1 1-2 equiv. 

Arsenic acid, 38 “ “ 20 or 2 1-2 equiv. 

518. Arsenious Acid , sometimes called the white oxide of arse¬ 
nic, and rats bane , is a white substance, offensive to the taste, 
and a deadly poison, not only when taken into the stomach, but 
when applied to a wound, or when its vapor is inhaled. Though 
soluble in warm water, a portion of the acid, in the form of a 
white powder, will be found suspended as the liquid becomes 
cool. This circumstance has sometimes led to the detection of 
attempts to ffestroy life by this poison. 

Th^re are different tests by which the presence of this mineral may be 
detected. In the solid state, it may be known, in the open air, when 
heated, by its peculiar odor, like that of garlic. In solution it forms a 
white precipitate with lime water : and a yellow sulphuret of arsenic 
with sulphuretted hydrogen ; the latter test is so certain, that, according 
to Orfila, it'would detect one one hundred thousandth part of white ar¬ 
senic dissolved in a liquid. Sulphuret of potassium, and sulphuret of 
sodium precipitate this substance in yellow flakes ; but it is necessary to 
add some drops of acetic or muriatic acid that may unite with the base of 
the sulphurets, otherwise there will be no precipitate. Writers on med¬ 
ical jurisprudence by omitting this circumstance, have led to errors in 
attempts to detect the presence of arsenic. In so important a trialas 
that of determining the presence of arsenical poison in the stomach of a 
deceased person, there should be a resort to various tests, and therefore 
while one portion of the contents of the stomach is subjected to the ac¬ 
tion of one test, other portions should be tried by other means. The 
nitrate of silver precipitates a white powder in solution of arsenical com- 


517. Compounds of arsenic and oxygen. 

518. Synonymes of arsenious acid. Poisonous. Action with water. 
Tests of arsenious acid. 

20 



226 


INORGANIC CHEMISTRY. 


pounds, which, with ammonia, forms a yellow arsenite of silver. Am* 
moniacal sulphate of copper produces an apple green precipitate, which 
is the arsenite of copper or Scheele's Green. 

519. Arsenic Acid may be obtained by boiling arsenious acid 
with nitric acid, which yields a portion of its oxygen, giving off 
nitric oxide. This acid has a sour metallic taste, reddens vege¬ 
table blues, and forms with alkalies neutral salts, called ar- 
seniates. 

520. Arsenic in powder, takes fire in chlorine gas, forming chloride of 
arsenic. It unites with iodine by a gentle heat, forming the iodide of 
arsenic , which is a deep red compound. Bromine , by mere contact with 
metallic arsenic, burns with vivid light and heat, forming a volatile 
bromide of arsenic. Jlrseniuretted hydrogen is highly destructive to ani¬ 
mal life. A German philosopher, M. Gehlen, in making experiments 
with it, inhaled its vapor, and died in consequence, with intense suffer¬ 
ing. It extinguishes combustion, but is itself kindled by burning bodies, 
and burns with a blue flame. 

The Sulphurets of arsenic exist as natural minerals. The red sulphuret 
is known by the name of realgar ; a yellow sulphuret is called orpiment; 
this is the basis of the paint known as king’s yellow. Tne sulphurets of 
arsenic, though poisonous, are less so than the acids. 

Antimony. 

521. The name of this mineral is supposed to be derived from 
anti , against, and monakos a monk, the improper use of it as a 
medicine, by a German monk, in the fifteenth century, having, 
as it is said, caused the death of many of his fraternity. What is 
termed crude antimony in commerce is the native sulphuret of 
this metal. In its pure state, antimony is a shining metal, of a 
silvery white color, a scaly texture, brittle, and gives off a pe¬ 
culiar odor on being rubbed. 

It melts below red heat; and when suffered to cool slowly, often pre¬ 
sents upon its surface marks of crystalization, resembling fern-leaves. 
It is not volatile ; and not acted upon by dry air, or oxygen. It fuses at 
810° F. and sublimes in dense white fumes, combining with oxygen. 
When in a state of powder it inflames spontaneously in chlorine gas, and 
burns with a bright white flame. The product is a liquid, which be¬ 
comes solid on cooling. This chloride from its consistence was formerly 
called butter of antimony. The per-chloride is obtained by adding nitro - 
muriatic acid, hydro-chloro-nitric, to antimony 3 it is a volatile, fuming 
liquid 

522. The Protoxide of antimony is obtained by dissolving in water, 
proto-chloride of antimony 3 a white powder is precipitated called pow¬ 
der of algaroth, which is a sub-chloride of antimony. A solution of pot- 

519. Mode of obtaining arsenic acid, its properties and salts. 

520. Combinations of arsenic with chlorine, iodine, bromine, hydro¬ 
gen and sulphur. 

521. Supposed derivation of the name antimony. Antimony of com¬ 
merce. Properties of pure antimony. Chlorides of antimony. 

522. Protoxide of antimony. 



ANTIMONY. 


227 


ash being added to this powder, the chlorine combines with the potash, 
and the metal uniting with the oxygen of the water, forms the protoxide 
of antimony. 

When heated to redness in an earthen crucible, antimony disengages 
a thick white smoke, which being condensed, forms a white crystalline 
substance formerly called argentine flowers of antimony ; this is similar 
in its composition to the protoxide. 

523. Dcutoxidc of antimony. When metallic antimony is digested in 
strong nitric acid, the metal is oxidized at the expense of the acid, and a 
white hydrate of the peroxide is formed ; on exposing this substance to a 
red heat, water and oxygen gas are disengaged, and the peroxide is re¬ 
duced to a deuloxide. The deutoxide, combines with alkalies, for which 
reason it has been called antimonious acid , and the salts antimonites. 

524. The Peroxide or antimonic acid forms salts with alkalies called 
antimoniates. 

525. The component parts of the compounds of antimony with oxygen 
are as follows, viz. 

Protoxide 44 dr one equiv. 8 or one equiv. 

Deutoxide 44 ditto 12 or 1 1-2 “ 

Peroxide 44 ditto 16 or 2 “ 

526. The Sulphuret of Antimony is found extensively as a na¬ 
tive combination ; it may also be prepared by art, by fusing anti¬ 
mony with sulphur, in the proportion of one equivalent of 
antimony 44, with one of sulphur 16 ; and the compound is, in 
all respects, similar to the native mineral. When this sulphuret 
is slowly roasted in a shallow vessel, it gradually loses sulphur, 
and attracts oxygen, and may then be melted into a glassy, semi¬ 
transparent substance, which is called the glass of antimony. 

The medicine known as tartar emetic is a triple compound of 
tartaric acid, protoxide of antimony and potassa, called antimoni- 
ated tartrate of potassa. 

527. Alloys of antimony. Antimony may be made to combine 
with most of the metals. A very slight mixture of it, not ex¬ 
ceeding thA 1-200th of the whole mass is sufficient to destroy 
the ductility of gold, and even its fumes alone will produce that 
effect. When combined with lead, it becomes the alloy called 
type metal, which is used for printing types. 

528. As a medicinal agent, when properly employed, this 
metal is highly valuable. It was not, however, until long after 
its discovery that its nature seems to have been well under¬ 
stood. From its fatal operation in many instances, the French 
parliament, early in the seventeenth century, at the suggestion 
of the medical faculty, proscribed the use of this medicine. 

523. Deutoxide of antimony or antimonious acid. 

524. Peroxide, or ahtimonic acid. 

525. Composition of the compounds of antimony and oxygen. 

526. Sulphuret of antimony. Glass of antimony. Tartar emetic. 

527. Alloys of antimony. 

528. Medicinal properties. 



228 


INORGANIC CHEMISTRY. 


This decree was, however, soon revoked and antimony again 
received in favor. 


Columbium. 

529. This metal was discovered by Mr. Ilachett of England 
in 1801, who detected it in a black mineral belonging to the Brit¬ 
ish museum, which had been sent by Gov. Winthrop from New 
London in Connecticut, to Sir Hans Sloane, founder of the mu¬ 
seum. The new substance was named Columbium, by its dis¬ 
coverer, in honor of the country from whence it had been sent. 
The mineral from which columbium is obtained is now found in 
Chesterfield Mass, and Haddam, Conn. 

Professor C. U. Shepard succeeded in obtaining the metal, by the de¬ 
composition of the mineral. But this is one among the refractory metals 
which are extracted with difficulty from rare minerals. Their discovery 
reflects honor on those who have, so indus'trously sought them out, and 
gives new interest to science . although this metal, hitherto, has not been 
applied to any useful purpose m the arts. 

About two years after the discovery of columbium, a Swedish Chemist 
extracted the same substance from the mineral called tantalite , and sup¬ 
posing it to be a new metal he called it tantalvm. In 1809, Dr Wollaston 
proved that this was identical with columbium, and tantalum was accord¬ 
ingly stricken from the list of simple bodies. 

530. Columbium is of a dark grey color, somewhat resembling 
iron. It is very hard, insoluble in acids, and soluble in alkalies. 
It unites with oxygen but in one known proportion, one equiva¬ 
lent of the metal, 144, being combined with one of oxygen 
8 = 152. This compound, sometimes called the oxide of colum¬ 
bium, reddens litmus paper, and combines with salifiable bases, 
properties which are characteristics of acids. The salts of this 
acid are called colurabaies . 


Titanium. 

531. Discovered in 1781, by Mr. Gregor of Cornwall, Eng¬ 
land, in black sand ; but its character was not then fully ascer¬ 
tained. Afterwards, in 1795. Klaproth published an analysis 
of a crystalized mineral, known at that time as red schorl; 
though he did not entirely succeed in reducing it to a metallic 
state he inferred that it was the oxide of a new metal, which he 

529. Discovery of columbium. Origin of the name, &c. Identity of 
tantalum and columbium. 

530. Properties of columbium and its combination with oxygen. Ox¬ 
ide of columbium. Its salts. 

531. Discovery of titanium. By whom named ? Dr. Wollaston’s 
discovery. Properties of crystals of titanium. Resemblance to iron py¬ 
rites. Titanium combined with iron, &c. Properties of the metal. 



CHROMIUM. 


229 


named titanium. In 1822, Dr. Wollaston discovered that some 
minute copper-colored crystals, found in the slag of an iron fur¬ 
nace at South Wales, and presented to him by the Rev. Dr. 
Buckland, consisted of this metal. 

They conducted electricity, had a specific gravity of 5, 3, and were so 
hard as to scratch a polished surface of rock crystal. They become oxi- 
idized, by being heated with nitre, and were converted into a white sub¬ 
stance, which was considered an oxide of titanium. Similar crystals of 
titanium have since been found at other iron works, where they have 
sometimes been mistaken for iron pyrites. In its purest native state, 
this metal is combined with a small portion of iron, which renders it 
slightly magnetic. The metal is infusible, it tarnishes in the air, and is 
easily oxidized by heat. It unites with oxygen in two proportions. 

532. The protoxide of titanium is of a blue color, and is supposed to 
exist in the mineral called anatasse , but its composition and properties 
are doubtful. With lime and silex it forms the mineral called sphene. 

533. The peroxide exists nearly pure in the mineral called titanite or 
rutile. When pure, this oxide is nearly white; it possesses some acid 
properties, and is sometimes called titanic acid. The oxides of titanium 
have been used in porcelain painting. Silliman states that titanium is 
found frequently in the primitive rocks of the United States. Its equiv¬ 
alent number is not fully known. 

Chromium . 

534. So named from the Greek, Kroma , on account of its 
tendency to form colored compounds. It was discovered by the 
French chemist, Vauquelin, in analyzing the chromate of lead, a 
beautiful red mineral from Siberia. It is a white and brittle met¬ 
al, susceptible of high polish, and only imperfectly fused at very 
high temperatures. It is not changed by air, but absorbs oxygen 
at a red heat. Sulphur, phosphorus and chlorine are the only 
combustible, non-metallic elements which combine with it. It 
exists in nature only in the state of a chromate or an oxide. 
Many of the gems owe their beautiful tints to this metal. 
Its acid gives the red color to the ruby: its oxide the green 
color to the emerald. Chromate of iron, is found in marble and 
serpentine, to which they are probably indebted for their beauti¬ 
ful variety of colors. New Haven and Milford in Connecticut, 
and Baltimore in Maryland, furnish fine specimens of chromate 
of iron. 

535. The usual method of obtaining chromium, is to procure chromic 


532. Protoxide of titanium. Anatasse. Sphene. 

533. Peroxide or titanite. Acid properties. Use of the oxides, &c. 

534. Derivation of the name chromium. Discovery, properties, &c. 
Combination with oxygen, and non-metallic combustible elements. How 
found in nature ? Coloring properties, &c. 

535. How obtained. How may chromium become changed to chromic 
acid. Its compounds with oxygen. 

20* 



230 


INORGANIC CHEMISTRY. 


acid by the. decomposition of the chromate of lead or iron and then to 
reduce the acid to a metallic state by heating it with charcoal; the oxygen 
is thus expelled. When fused with nitre, chromium is oxidized, and con¬ 
verted into chromic acid. 

Chromium unites with oxygen in two proportions, viz. 

Chromium. Oxygen. 

Green oxide. 32 or one equiv. 8 or 1 equiv. 

Chromic acid. 32 or ditto 20 or 2 1-2 equiv. 

536. Protoxide of Chromium. Is a green, pulverulent sub¬ 
stance, infusible, undecomposable by heat, and insoluble in wa¬ 
ter. Oxygen gas has no action upon it at any temperature. It 
w r as discovered by Vauquelin. It may be obtained by decom¬ 
posing the ch romate of mercury at a very high temperature. 
The mercury is disengaged in vapor, and the chromic acid re¬ 
solved into oxygen and the protoxide of chromium. This oxide 
is sometimes found on the surface of chromated lead ; it is this 
which causes the green color of the emerald and many mag¬ 
nesian rocks. It is employed in the arts ; it is used in porce¬ 
lain painting to give a fine green color; and is the coloring • 
used in artificial gems which are made to imitate the emer¬ 
ald. In Chemistry this oxide is employed for extracting the 
metal. There, is a brown oxide which some suppose to be a dis¬ 
tinct substance composed of one equivalent of chromium and 
one of oxygen ; it has been called chromous acid , and deutoxide 
of chromium. By others it is considered a mixture of green 
oxide and chromic acid. 

537. Chromic Acid exists in nature, in combination with lead, 
forming the chromate of lead of Siberia and Brazil; and in the 
ruby to which it imparts its peculiar hue of dark red. It may 
be extracted from the chromate of baryta, dissolved in dilute 
sulphuric acid, the sulphate of baryta is precipitated, and chro¬ 
mic acid is in solution. This solution is filtered and evaporated 
to dryness. It may be obtained from its concentrated solu¬ 
tion in ruby red crystals. It is very solubl6 in water, has a 
sour taste, and forms colored salts, called chromates , with alka¬ 
line bases, and metallic oxides. When exposed to strong heat, 
oxygen is disengaged, and the acid changes to the green oxide. 
It destroys the color of indigo, and most vegetable and animal 
coloring matters ; a property advantageously employed in calico 
printing, and which depends on the facility with which it yields 
its oxygen. It gives with mercury, a cinnibar red ; with silver^ 

536. Properties, discovery, and mode of obtaining protoxide of chrom¬ 
ium. Its use. Brown oxide of chromium. 

537. Chromic acid. 




MOLYBDENUM. 


231 


a carmime red ; with lead, orange yellow ; with tin, green ; and 
w ith borax, a beautiful emerald-green color. 

538. Fluo-chromic acid gas is disengaged, when a mixture of fluorspar 
and chromate of lead is distilled with sulphuric acid, in a leaden retort. 
This gas acts rapidly upon glass. Chromium forms a red gas with chlo¬ 
rine, called chlOro chromic acid,gas ; it is obtained by the action of fum¬ 
ing sulphuric acid on a mixture of chromate of lead, and chloride of 
sodium. A chloride of chromium, is obtained by transmitting dry chlo¬ 
rine over a mixture of chromium and charcoal, heated to redness in a 
porcelain tube. This chloride is a crystaline sublimate of a purple 
color. 

Sulphuret of Chromium is a dark grey substance, consisting of one 
equivalent of each of its elements. Fhosphuret of Chromium is a porous 
substance, ofa light gray color. 

MOLYBDENUM. 

539. The name of this mineral is from the Greek molubdai - 
na, lead, this metal being at first confounded with black lead, 
now known by the Latin name, plumbago. All metals which 
are light, friable, soft, of a greasy feel, and which stain the fin¬ 
gers, or paper, were formerly supposed to be the same sub¬ 
stance. Scheele first distinguished between molybdenum and 
plumbago ; the latter being a carburet of iron, the former a new 
metal, found in combination w r ith sulphur. Molybdenum has not 
been found pure, in a native state, and only in a state of a sul¬ 
phuret of molybdenum , and a molybdate of lead , the former is com¬ 
mon in the Alps, the latter in Austria. Silliman states that these 
compounds are found, in small quantities, in the primitive rocks 
of the United States. 

540. When the sulphuret of molybdenum is distilled in nitric acid, 
molybdic acid is obtained, in the form of a yellowish white, heavy pow¬ 
der. This being mixed with oil, and placed in a crucible lined with 
charcoal, is heated intensely, and the acid disengaging its oxygen, is re¬ 
duced to a pure metallic state. Molybdenum is among the most infusi¬ 
ble metals. At the ordinary temperature, it has no action upon oxygen ; 
but at a red heat, it unites with it, forming a white sublimate of molyb¬ 
dic acid. 

541. This metal has never been obtained, except in small 
globules of a brittle texture and a gray color. The protoxide is 
black, and consists of one equivalent of oxygen, and one of the 
metal. The deutoxide , or molybduous acid is brown, and con- 

538. Fluo-chromic acid gas. Chloro-chromic acid gas. Chloride of 
chromium. Sulphuret of chromium. 

539. Derivation of the name Molybdenum. By whom distinguished 
from plumbago ? In what state, and where found. 

540. Molybdic acid. Infusible nature of this metal. Action with 
oxygen. 

541. In what form obtained ? Character of its oxides and acid. Chlo¬ 
rides. Sulphuret. Uses of the metal. 



232 


INORGANIC CHEMISTRY. 


tains two equivalents of oxygen, and one of the metal. Molyb- 
dic acid is yellowish white, and contains three equivalents of ox¬ 
ygen to one of the metal. Berzelius states that there are three 
chlorides of molybdenum, the compounds of which are analo¬ 
gous to the compounds of this metal with oxygen. A native 
sulphuret of molybdenum, of a ruby-red color has lately been 
discovered, analogous to molybdic acid, in its constituents. This 
metal has yet been of little use in the arts ; but its coloring prop¬ 
erties are peculiar, and may, hereafter, be advantageously ap¬ 
plied. 

TELLURIUM. 

542. Was discovered in 1782, by M. Muller, in the gold 
mines of Transylvania, and named by Klaproth, from Tellus , the 
earth, in accordance with the ancient method of naming the 
metals after the planets. Tellurium has been found in the state 
of an alloy with gold, silver, lead, copper, iron, and sometimes 
with all these metals united.* It is brittle, of the color of tin, 
with some lustre. It fuses readily, and is the most volatile of 
all the metals, except osmium and mercury. When distilled in 
close vessels, it sublimes, and its vapor condenses into brilliant 
metallic drops. When heated in contact with the air, it oxidi¬ 
zes, and burns with a sky-blue flame, edged with green. It 
gives off a gray smoke, of a pungent, nauseous odor, resembling 
that of the vapor of selenium, and which has been compared to 
the odor of decayed horse-radish. This vapor condenses into a 
white oxide of tellurium , supposed to be composed of one equiv¬ 
alent, or 32 parts of the acid, and one equivalent, or 8 parts of 
oxygen. It unites both with alkalies and acids, to form salts. 
Tellurium has been hitherto a rare mineral, scarcely found ex¬ 
cept in Transylvania. Silliman supposes it exists in the town 
of Munroe in Connecticut, but this fact seems not fully estab¬ 
lished. 

543. Telluretted Hydrogen gas may be obtained by mixing together 
oxide of tellurium, hydrate of potassa, and charcoal, at a red heat, and 
acting upon the mixture by dilute sulphuric acid. The combination of 
hydrogen and tellurium which ensues, is a gas which, like sulphuretted 
hydrogen, manifests acid properties. It forms a claret colored solution 
with water, burns with a black flame, and deposits the oxide of the 
metal. 


* For the process of obtaining the metal from its ores, see Die. of 
Chem., article Tellurium. See also Silliman’s Elements, Vol. II. p. 160. 


542. Discovery of tellurium, and origin of its name. With what 
metals found P Properties. White oxide of tellurium. Localities of 
tellurium. 

543. Telluretted hydrogen gas. 



TUNGSTEN. 


233 


TUNGSTEN. 

544. This metal was first discovered in Sweden; its name 
signifies, in the Swedish language, heavy stone. It is the heavi¬ 
est metal known, except iridium, gold, and platinum. The ores 
of this metal are tungsten or tungstate of lime , yellow oxide of 
tungsten , and wolfram or tungstate of iron , and manganese. In 
these ores, tungsten exists in the state of tungstic acid, and has 
been found native in no purer form. The mineral is first decom¬ 
posed in order to obtain the acid ; the latter, in the form of a 
whitish powder, is then made into a paste with oil, and heated 
intensely in a crucible, lined with charcoal. The presence of 
small metallic globules, indicates the reduction of the metal. It 
has never been obtained in large masses. It is of an iron gray 
color, of a brilliant lustre, and so hard as scarcely to yield to the 
file. It is very infusible. 

545. There are two known compounds of this metal with oxygen, viz. 
The-darh brown oxide and the yellow acid. 

The oxide of tungsten is formed by the action of hydrogen gas on 
tungstic acid, at a low .heat. It is of a dark chocolate color; and when 
polished resembles copper. This oxide does not unite with acid to form 
salts. 

Tungstic acid may be prepared by the action of muriatic acid on wol¬ 
fram , (or native tungstate of iron and manganese,) or by heating the 
brown oxide to redness, in open vessels. This acid is of a yellow color ; 
it has no action on litmus paper, but with alkaline bases, forms salts, 
called tungstates. But its acid properties are so feeble, that its salts are 
readily decomposed by most other acids. This acid is found to be com¬ 
posed of 96 parts of tungsten, and 24 parts of oxygen; consequently 96 
is the atomic weight of tungsten, and 129 the equivalent of its acid. 

The oxide consists of one equivalent of the metal=96, and two equiv¬ 
alents of oxygen=16. 

Tungsten unites in three proportions with chlorine, forming chlorides. 
The ores of tungsten have been found in the cobalt mines in Chatham, 
and Monroe in Connecticut. 

546. Vanadium , was recently discovered by M. Sefstrom, di¬ 
rector of the school of mines at Fahlun in Sweden. The prop¬ 
erties of this metal resemble those of chromium, and the metals 
might easily be confounded. Professor Del Rio, many years 
since, supposing that he had found a new metal in the brown 


544. Discovery of tungsten. Origin of the name. Specific gravity. 
Ores of thi^ metal. How obtained from its ores P Color, lustre, &c., 
of the metal. 

545. Oxide of tungsten. Tungstic acid. Composition and equiva¬ 
lents of the acid and oxide of tungsten. Chlorides. Localities of tung¬ 
sten ores. 

546. History of the discovery of vanadium. Acid and oxide of vana¬ 
dium. 



234 


INORGANIC CHEMISTRY. 


lead ore of Zimapan in Mexico, sent some specimens of it to the 
French chemists at Paris, who pronounced them to be merely 
impure chromium. Since the discovery of vanadium the opin¬ 
ion of Del Rio has been confirmed, and the ore pronounced to 
be a vanadiate of lead ; the same substance has been lately dis¬ 
covered in a mineral from Wanlockhead in Scotland. Like chro¬ 
mium, it appears to possess peculiar coloring properties. Van - 
adic acid is red, and fusible. The oxide is of a dark brown 
color. 

547. Uranium was discovered in 1789, by Klaproth, and named 
from the Greek, uranos , the heavens. The ores which contain 
this metal, are very rare. Combined with carbonic acid, it forms 
chalcolite , or green mica. Its ores are reduced with difficulty, 
and it has only been obtained in small quantities. It is of a dark 
grey color, hard, and brittle. There are two known compounds 
of this metal with oxygen. The protoxide is of a dark green 
color; it unites with acids, forming salts of a green color. It is 
employed in the arts, for giving a black color to porcelain. The 
peroxide is of an orange color, and most of its salts have a simi¬ 
lar tint. It is used for giving an orange color to porcelain. 

MANGANESE. 

548- Manganese is never found native in the metallic state, 
the substance known in the arts by this name, being an impure 
oxide. Owing to the great affinity of this metal for oxygen, it 
is usually found in nature combined with it, though sometimes 
in the state of a phosphate, and a sulphuret. 

“ The black oxide of manganese was described by Scheele,in the year 
1774, as a peculiar earth ; Gahn subsequently showed that it contained 
a new metal, which he called magnesium , a term since applied to the 
metallic base of magnesia, and for which the words manganesium and 
manganum have been applied.”— Turner. The pure metal may be ob¬ 
tained by heating, for an hour or two, over a powerful air furnace, a 
mixture of the black oxide, oil, and charcoal, in a black lead crucible ; 
on cooling the mixture, metallic masses will be found with the charcoal 
at the bottom of the crucible. 

549. This metal, in some of its properties, resembles iron ; it 
is of a gray color, very hard and brittle. It is very infusible, 
readily acted upon by air, tarnishing and at length crumbling 
into a brown powder. At the ordinary temperature, it has no 


547. Discovery of uranium. Name. Ores. Properties. Com¬ 
pounds with oxygen. 

548. How is manganese found in nature ? By whom discovered. 
Original name. How obtained pure ? 

549. Properties. Action with air or oxygen, or with hydrogen, nitro¬ 
gen, &c. Phosphuret. Chloride. 



MANGANESE. 


235 


action on atmospheric air, or oxygen gas ; but at a high temper¬ 
ature, it soon oxidizes. It is not acted upon by hydrogen, ni¬ 
trogen, boron, or carbon, and does not easily combine with sul¬ 
phur, though a natural sulphate of manganese exists. At a high 
temperature, it combines with phosphorus, forming a white, and 
brilliant phosphuret. It absorbs chlorine rapidly, forming a very 
soluble, greenish chloride. 

550. There has been much diversity of opinion among Chem¬ 
ists, with respect to the number of compounds of manganese 
with oxygen. There are three oxides whose composition ap¬ 
pears established, viz. 


Manganese. 


Oxygen. 

8 or one equiv. =36. 
12 or 1 1-2 “ “ 40. 
16 or 2 “ “ 44. 


Protoxide 28 or one equiv. 
Deutoxide 28 “ 

Peroxide 28 “ 


The protoxide , or green oxide of manganese, is obtained by igniting 
the deutoxide in contact with hydrogen or charcoal. Its rich green color 
on exposure to the air, changes to brown. 

The deutoxide , or brown oxide, remains when the peroxide is heated 
to afford oxygen gas. It is found in large native crystals, in the Hartz 
mountains. 

The peroxide , called also the black oxide, is that which, by heat, dis¬ 
engages half an equivalent (4 parts,) of oxygen, and is therefore com¬ 
monly used for the purpose of obtaining oxygen gas. To obtain oxygen 
gas from the peroxide of manganese, it is sufficient to apply red heat to 
the latter, but if sulphuric acid be added to the peroxide of manganese, 
the presence of the acid appears to increase the disposition of the perox¬ 
ide to give up its oxygen, by combining with the deoxidized manganese. 
This is a case of disposing affinity. This oxide occurs in large' masses of 
an earthy appearance, and mixed with other substances, such as oxide of 
iron, carbonate of lime, and siliceous earth. It is sometimes found in 
groups of crystals, and is an essential ingredient in a mineral called black 
toad. 

551. A red oxide of manganese, supposed by some, to be a 
mixture of the peroxide, and the deutoxide, and by others, a def¬ 
inite compound, imparts to glass or borax a beautiful violet color ; 
the amethyst owes its rich color to the presence of this oxide. 

If a mixture of one part of powdered black oxide of manganese, and 
three parts nitrate of potassa, be thrown into a red hot crucible, and con¬ 
tinued there until no more oxygen is disengaged, a green colored, fused 
mass is obtained, called mineral chamelion , from its property of assuming 
different colors. On putting this substance into water, a green solution 
is obtained, which soon passes into blue, purple, and red; at length a 


550. Composition and equivalents of the oxides of manganese. Pro¬ 
toxide. How obtained. Its properties. Deutoxide. Peroxide. Use 
of sulphuric acid in the process for obtaining oxygen from the peroxide 
of manganese. 

551. Red oxide of manganese. Mineral chamelion. Manganesic 
acid, how formed ? Manganesious acid, how formed ? 



236 


INORGANIC CHEMISTRY. 


brownish matter, the red oxide, subsides, and the liquid becomes, color¬ 
less. These phenomena are explained as follows: the peroxide of man¬ 
ganese, when fused with potassa, absorbs oxygen from the atmosphere, 
and is thereby converted into manganesic acid , which unites with the al¬ 
kali ; the changes of color, are owing to the combination of manganesic 
acid with different proportions of potassa. By evaporating the red so¬ 
lution rapidly, small, prismatic, purple crystals are obtained; these are 
the mangancsiate of potassa. 

There is also supposed to be a mangancsious add , or an acid with a 
smaller proportion of oxygen. The manganesiate of potash, be‘ing acted 
upon by substances that attract oxygen, as alcohol, and carbonate of 
manganese, loses its red color, and becomes a green manganesife of pot¬ 
ash, the acid in the latter being reduced to the manganesiows, containing 
but three equivalents of oxygen, while the manganesic contains four 
equivalents. 

552. Chlorine gas for chemical experiments, and liquid chlorine for 
bleaching, in large manufactories, are usually obtained by the agency of 
the peroxide of manganese in combination with hydrochloric (muriatic) 
acid. The acid consisting of one equivalent of chlorine and one of hy¬ 
drogen, is decomposed by the loss of its hydrogen, which, by uniting 
with one equivalent of oxygen given off by the peroxide of manganese, 
produces one equivalent of water. The chlorine being set free, passes 
off in a gaseous state. The loss of oxygen by the manganese, having 
converted the peroxide to a protoxide, the latter unites with an equiva¬ 
lent of undecomposed hydro-chloric acid, and forms a hydro-chlorate (or 
muriate) of /the protoxide of manganese. 

Manganese unites with chlorine in two proportions, forming a pink 
colored proto-chloride, with onq equivalent of each element; and a per- 
chtoride with one equivalent of manganese aud four of chlorine. The 
latter is prepared by putting sulphuric acid into a solution of manganese, 
and then adding fused sea-salt. The muriatic and manganesic acids mu¬ 
tually decompose each other, producing water and the per-chloride of 
manganese ; the latter is a vapor, which at first appears of a yellowish 
green tint, but condenses into a dark colored liquid. When the per- 
chloride vapor is introduced into a flask, the sides of which are moist, 
the color of the vapor changes instantly, and a rose-colored smoke ap¬ 
pears. Manganese combines with fluorine, forming a fluoride of manga¬ 
nese, which at first appears in the form of a greenish yellow vapor. 
When mixed with atmospheric air, it assumes a beautiful purple red 
color. It acts on glass. On account of rendering glass colorless, the 
black oxide of manganese was formerly, called by the artists, glass-ma¬ 
ker's soap. According to Pliny it was used two thousand years ago. 

553. Cobalt. The name of this mineral is derived from coba- 
lusj the supposed demon who infests mines, impeding the opera¬ 
tions of the miners, and destroying their lives. This metal, 
though employed in the fifteenth century for the purpose of col¬ 
oring glass blue, was not known to he a simple element until ob¬ 
tained from its ores by Brandt of Sweden, in 1733. It is a 
solid metal, hard, brittle, of reddish grey color, and weak me- 

552. Process for obtaining chlorine by the aid of per-oxide of manga¬ 
nese. Chlorides and fluoride of manganese. Fluoride of manganese? 

553. Origin of the name Cobalt. Discovery. Properties. Ores. 
How obtained from the arsenical ore ? 





cobalt. 


237 


tallic lustre. It is magnetic, a property which was formerly hs- 
cribed to the presence of some iron, but a magnetic needle has 
been made of pure cobalt. It is found in connexion with ores 
of iron and copper, but chiefly with arsenic. When the arseni¬ 
cal ore of cobalt is heated, the arsenic exhales in vapor, and the 
oxide of cobalt remains. This operation is carried on extensive¬ 
ly in Saxony ; the labor being performed by criminals who are 
condemned to be thus slowly destroyed, for crimes which incur 
the punishment of death. The white oxide of the arsenic of 
commerce is mostly thus obtained. 

554. Protoxide of Cobalt , is formed when cobalt is slowly 
oxidized by being heated in the open air. It is at first blue, 
gradually becomes darker, and an intense heat melts it into a 
blue-black glass. The Peroxide is formed by igniting the protox¬ 
ide, and exposing it to the action of the oxygen of air; it rapid¬ 
ly absorbs oxygen, becoming first of an olive-green color, and 
then black. By continued powerful heat, a portion of oxygen is 
expelled, and the substance becomes again a protoxide. 

Though we have classed cobalt with the metals which form 
acids with oxygen, there is some doubt as to the existence of a 
Cobaltic Acid. M. Gmelin from a solution of ammonia and ni¬ 
trate of cobalt obtained crystals of a double salt, supposed by him 
to consist of nitrate, and cobaltate of ammonia, the latter consist¬ 
ing of cobaltic acid and ammonia. 

The Zaffre of commerce is an impure oxide of cobalt. Smalt 
is formed by heating the oxide of cobalt with a mixture of sand 
and potassa ; the result is a beautiful blue colored glass. This, 
when ground fine, is called powder blue ; it is used by laundresses 
as a very delicate bluing for muslins and laces, in paper manu¬ 
factories to give a blue tint to paper, and is erpployed in painting. 
Cobalt being the only blue color which w ill endure the heat of a 
furnace, is highly valuable to manufacturers of porcelain. The 
ancients are supposed to have used this oxide, mixed with oil m 
their painting ; and this is given as a reason for the blue drapery 
and skies, in some old pictures being so durable. 

555. Sympathetic Ink may be made by digesting the oxide of cobalt in 
muriatic acid, and diluting with water. Words written with this solu¬ 
tion of muriate of cobalt will be invisible till brought near the fire, when 
the writing will appear of a bright green tint. The acetate and nitrate 

554. Protoxide of cobalt. Per/xide. Statement of M. Gmelin re¬ 
specting the formation of cobaltic acid. Sulphuret of cobalt. Phosphuret. 
Chloride. Zaffire. Smalt. Powder-blue. Use of cobalt in the manu¬ 
facture of porcelain. 

555. Sympathetic ink. Localities of cobalt. 

21 



238 


INORGANIC CHEMISTRY. 


Fig. 88. 



of cobalt will present a blue colour 
on being warmed. Let a paper 
fire screen represent a landscape 
where the trunks and leafless 
branches are sketched in Indian 
ink, and paint the foliage and fore¬ 
grounds with the muriate, and the 
sky and distant mountains with the 
acetate or nitrate of cobalt; while 
the picture is cold, it represents 
merely the outline of a landscape, 
or a winter scene, as at a; on 
bringing it near the fire, it will be 
'transformed to a summer land¬ 
scape, with green trees and a clear 
blue sky, as at b. On being removed from the fire, the scene will grad¬ 
ually lose its verdure, and resume its winter dress. 

The cobalt of commerce was at first wholly furnished by Sax¬ 
ony. The ores of this metal are now found abundantly in Swe¬ 
den, in a mine in Cornwall in England, and in various parts of 
America. In Franconia, in New Hampshire, cobalt is found in 
arsenical iron ore ; and in Chatham, Connecticut, associated with 
nickel. It has been found in many specimens of aerolites or 
meteoric stones. 

556. Tin. This appears to have been among the few metals 
known in the first periods of history. It is named by Moses in 
connexion with u gold, silver, brass, iron, lead, and every thing 
that may abide the fire.” The Phoenicians obtained it in com¬ 
merce, passing in their wonderful voyages the pillars of Her¬ 
cules,* and visiting Britain, the Ultima Thule | of that period. 
The most ancient and extensive tin mines are Cornwall in Eng¬ 
land. It is found in primitive mountains, in Saxony, Siberia, 
France, and Mexico. 

The alchemists, who often divided their attention between the 
mysteries of astrology and alchemy, considered that there were 
some secret sympathies between the planets and the metals, na¬ 
med tin, Jupiter , because like that planet it had a brilliant ap¬ 
pearance. It was called also by the Latin name, Stannum. 

557. Tin Plate , in which form this metal is used for a variety 
of purposes, consists of sheets of iron coated with tin. Tin Foil 
is made from the finest tin, beaten out wfith a hammer. Tin is a 
white, brilliant metal, with a silvery lustre. It is neither very 
hard nor ductile, and has little tenacity. It is flexible, and in 
bending gives a peculiar crackling sound.' It is among the most 


Straits of Gibralter. 


t The remotest land. 


556. Ancient use of tin; its localities and synonymes. 

557. Tin Plate. Tin Foil. Properties of tin. Combination with oxygen. 



TIN AND OXYGEN. 


239 


fusible of the metals ; it is vaporized by the heat of the com¬ 
pound blow pipe. It is so soft as to be cut with a knife, or 
scratched with a pin. Its odor and taste are peculiar ; it tar¬ 
nishes on exposure to the air. If steam be passed over tin heat¬ 
ed to redness, it decomposes the water and combines with the 
oxygen, while the hydrogen gas is disengaged. 

558. Tin and Oxygen. The protoxide of tin is obtained when tin is 
kept for some time melted in an open vessel, or in contact with the air ; 
oxygen is absorbed and the product is a gray powder. The Protoxide 
has such an affinity for oxygen, that when heated to redness in open 
vessels it unites with another proportion, and becomes the peroxide. 
The latter is of a straw yellow color ; and exhibits the character of an 
acid capable of uniting with potash and other alkalies. It has been cal¬ 
led by Berzelius Stanic acid, and we have therefore classed tin among 
those metals which form acids both oxygen. 

559. Tin combines with sulphur , forming a blueish and metallic 
pr oto-sulphur et, and a beautiful gold-colored bi-sulphuret , which is used 
to give a golden color to bronze, and japanned articles, and to excite 
electrical machines. JVitric acid oxidizes but does not dissolve tin. The 
nitro-muriatic acid dissolves it with effervescence, forming a salt called 
th e per-muriate of tin, which is employed in dyeing, especially to change 
the color of cochineal from crimson to a bright scarlet. The proto-muri¬ 
ate of tin is prepared by boiling tin filings in muriatic acid. It is much 
used as a deoxidizing substance, especially for precipitating metals from 
their solutions. 

There are two chlorides of tin ; the proto-chloride is a gray substance, 
of a resinous lustre. The bi-chloride , formerly called the fuming liquor 
of Libavius , is a volatile liquid, which emits copious white fumes. It in¬ 
flames the oil of turpentine ; and has a strong attraction for water, which 
changes it to the permuriate. The bi-chloride may be formed by heating 
metallic tin in an atmosphere of chlorine ; it contains two equivalents of 
chlorine, united to one of the metal. 

Mloys of Tin. The alloys of fin with copper in different proportions 
form bronze, bell metal, and a beautiful white substance used for the re¬ 
flectors of telescopes. 


LECTURE XXII. 

METALS OF THE SECOND CLASS. 

Alkaline metals , or those whose oxides are fixed alkalies , or alkaline 
earths .— Order 1, Metals which , with oxygen, form the 
fixed alkalies. 

560. The metals of this class, from their apparent doubtful 


558. Compounds formed by tin with oxygen. 

559. The combinations of tin. Alloys. 

560. Why were the metals of this class called metalloids ? Order 1. 

Order 2. 





240 


INORGANIC CHEMISTRY. 


character, were at first called metalloids * They differ from 
copper, lead, gold, &c., and other well known metals, in their 
ess specific gravity, some being lighter than water. From their 
great affinity for oxygen, it is very difficult to obtain or preserve 
them in a state of purity; a circumstance which has hitherto 
presented an obstacle to their study. In their metallic lustre, 
and in uniting with oxygen to form oxides which, in their turn 
form salts with acids, they exhibit distinguishing properties of 
metals ; and being now ranked as such, the term metalloids, can 
scarcely be applied to them. 

We shall divide this class into two orders ; the first order in¬ 
cluding metals which with oxygen, form the fixed alkalies , the 
second including metals which with oxygen form alkaline earths. 

Order I. —Metals , which, with oxygen, form the fixed alkalies , 
as Potassium, Sodium and Lithium. 

561. The metals of this order have so great an attraction for 
oxygen, that they decompose water at the moment of contact, 
and are oxidized with disengagement of hydrogen gas. The 
resulting oxides are distinguished by being caustic, and soluble in 
water, and by possessing highly alkaline properties ;—that is, 
they are hot, and biting to the taste, soluble in water, change 
vegetable blue colors green, and yellow colors brown, and have 
a caustic action on animal substances. They are called alkalies , 
and their metallic bases are called alkaline , or metals. Ammonia 
is an alkali, but its base is not a metal, like the bases of potassa, 
and soda; it being, as we have already shown, a compound of 
nitrogen and hydrogen. Sir Humphrey Davy, after having dis¬ 
covered the metals, potassium and sodium, in two of the alkalies, 
was induced to make a series of experiments upon ammonia, 
with the expectation of discovering ammonium. But instead of 
this base, the decomposition of ammonia resulted in the disen¬ 
gagement of the two non-metallic elements, hydrogen and ni¬ 
trogen. 

562. Potassium. This metal is obtained by the decomposition 
of potassa, (or potash,) which was, formerly, considered as a 
pure alkali, but is now known as the oxide of potassium. Sir 
Humphrey Davy, about the year 1807, became deeply interested 
in experiments on voltaic electricity; having first observed its 

* The Greek termination is from eidos , similar to \ the term metalloids 
signifies similar to metals. 


561. Attraction of these metals for oxygen. General properties of the 
oxides of these metals. What alkali has not a metallic base ? Names of 
the metals of this order. 

562. What substance contains potassium ? History of the discovery of 
the metallic bases of potassa and soda by Davy. 



POTASSIUM. 


241 


power in separating the elements of bodies known to be com¬ 
pound, he was led to examine its effects on potash and soda, un¬ 
til that time ranked among undecomposable elements. His first 
attempts on those alkalies, were made upon their aqueous solu¬ 
tions, but the water only was decomposed. He then caused a 
thin piece of pure hydrate of potassa, slightly moistened for the 
purpose of increasing its galvanic power, to communicate with 
the opposite poles of a powerful voltaic apparatus. , The potash 
soon became fused ; oxygen gas was evolved at the positive pole, 
and small metallic globules appeared at the surface connected 
with the negative pole. The active and comprehensive mind 
of Davy, on witnessing the success of the experiment, anticipat¬ 
ed the great changes which his discovery was destined to pro¬ 
duce in chemical science. Possessing the rare combination of 
ardent enthusiasm with cool philosophical research, he must 
have contemplated the victory of his genius with peculiar emo¬ 
tions. He foresaw that the elevation of his fame must be com¬ 
mensurate with that immortal science, the boundaries of which 
his labors have done so much to enlarge. 

563. The discovery of potassium, by Davy, stimulated the French 
Chemists to new efforts, and Gay Lussacand Thenard, in 1810, succeed¬ 
ed in obtaining the metal, without the aid of electricity, and in greater 
quantities than Davy had done. Their prooess consists in bringing 
fused hydrate of potash, in contact with iron turnings, heated to white¬ 
ness in a curved gun-barrel. The iron attracts the oxygen from the al¬ 
kali, and its metallic base is disengaged. 

The curved gun-barrel is represented at «, b , and/; the iron turnings 
are placed within, between/, and 6, which part is covered with a lute of 
infusible clay, made of five parts of sand, and one of potter’s clay. Be¬ 
tween a and b , are placed pieces of solid hydrate of potassa. A tube of 
safety is to be luted to the end, a, and immersed in mercury in the glass 
vessel, m. To the smaller end of the barrel, is fitted a piece of copper 
tube, and to this, a small copper receiver A, which is to receive the po¬ 
tassium. A tube of safety, i , communicating with this receiver, dips 
into mercury contained in the vessel, b. The furnace should now be 
heated until the barrel between b and/, or that portion containing the 
iron turnings, is of a white heat, the other parts of the barrel being kept 
cool by the application of wet cloths. The barrel having become white 
hot, the hydrate of potassa is melted by igniting charcoal contained in 
the moveable cage, k , and will then flow down upon the ignited iron 
turnings, hydrogen gas which was contained in the hydrate of potash, 
will issue through the safety tube, i; the oxygen of the potassa will 
combine with the iron turnings, while the potassium passing off in va¬ 
por, will be condensed in the copper receiver at /*, 

563. Process discovered by Gay Lussac and Thenard, for obtaining 
potassium without the aid of electricity. 

21* 




242 


INORGANIC CHEMISTRY. 


Fig. 89. 



564. Potassium resembles other metals in opacity, lustre, 
malleability, conducting power of heat and electricity, and in 
its chemical affinities ; but differs from most of them in being of 
a less specific gravity than water. Its affinity with oxygen is so 
great, that it cannot be preserved, except immersed in some sub¬ 
stance, from which oxygen is excluded, such as ether, or naptha, 
or in exhausted glass tubes hermetically sealed. 

At 32° Fahrenheit, it is brittle, and when broken, exhibits 
through a microscope, a white, crystalline appearance. It is 
solid at the common temperature, though soft, and easily mould¬ 
ed with the fingers.. In color and lustre, it resembles mercury ; 
its specific gravity is 0.865. It becomes fluid at 150^ Fahren¬ 
heit, and at a red heat, sublimes in the form of a greenish vapor. 
On exposure to the air, it tarnishes, becomes of a bluish color, 
and changes into the protoxide of potassium. When heated with 
oxygen gas, it burns with intense light and heat, forming, by its 
combination with oxygen, the deutoxide of potassium. When 
thrown upon water, potassium acts with great violence, swim¬ 
ming on its surface, and burning with great splendor ; hydrogen 
is evolved, and oxide of potassium is found in solution. If ice 
be used instead of water, it burns with equal force. This effect 
is owing to its rapid absorption of oxygen, from which so much 
caloric is disengaged, that the hydrogen gas, resulting from the 
decomposition of water, is inflamed. 

565. There are two oxides of potassium. 

564. Resemblance of potassium to other metals; its difference in one 
particular. Why potassium cannot be kept in the open air. Properties. 
Effects of exposure to the air. Of burning in oxygen gas. Action with 
water. 

565. Composition of the oxides of potassium. Synonymes of the pro¬ 
toxide of potassium. Potash of commerce, how obtained? Different 
proportions of potash in plants. Properties of potash. 





































POTASH. 


243 


Potassium. Oxygen. 

Protoxide 40 or 1 equivalent. 8 or 1 equivalent. 

Peroxide 40 “ ditto “ 24 or 3 equivalents. 

Protoxide of potassium , or potassa, is commonly known by the 
name of potash , from the pots or vessels in which it was made. 
It was at first called kali , and vegetable alkali , on account of its 
being procured from the lixiviation of vegetable ashes ; but it is 
now known to exist in earths, and mineral combinations, from 
which it is imbibed by plants. The potash of commerce, is 
chiefly obtained by evaporating the ley of wood, or vegetable 
ashes. Plants of a soft texture are found to yield more of the 
saline matter, than those with woody fibre. Resinous wood af¬ 
fords little alkali ; for which reason, the ashes of pine wood are 
little valued in families for soap-making. The protoxide of po¬ 
tassium, or potash, (but generally termed, in Chemistry, potas¬ 
sa,) is a white solid substance, highly alkaline, and of a greater 
specific gravity than the metal. It has so great an affinity for 
water, that it readily absorbs it from the air, forming with it the 
hydraie of potassa , composed of one equivalent of potassa, and 
one of water. 

566. The peroxide of potassium is formed when potassium burns in tho 
open air, or in oxygen gas. It is yellowish green, and gives the alkaline 
tests with vegetable colors. It was discovered by Gay Lussac and 
Thenard. 

The hydrate of potash , or caustic potash, is the per¬ 
oxide of potassium, combined with one equivalent of 
water ; and such is the affinity between them, that 
the water cannot wholly be expelled by the most 
intense heat. It is a white, solid mass, which fuses 
at a red heat, disengaging caustic, alkaline vapors. 
This substance is often cast into sticks for the use of 
surgeons, who employ it as a caustic. Pure hydrate 
of potassa is obtained by boiling a solution of potash 
or pearlash with quick lime. This solution is then 
to be filtered through a funnel, the throat of which is 
covered with folds of linen ; but since potash ab¬ 
sorbs carbonic acid rapidly, when exposed to tho 
atmosphere, Mr. Donovan invented the filtering ap¬ 
paratus here represented. 

A is the filtering funnel, having its throat obstruct¬ 
ed by a fold of linen to serve as a strainer; the so¬ 
lution being poured in through the mouth at 6, the 
funnel is closed by a cork fitted to the tube, c, and 
connected at a, with the receiving vessel, D. The 
filtration will now proceed at the slow rate which 
the nature of the operation requires, and without exposure to any 
more air than was contained in the vessels at the beginning. In order 

566. Peroxide of potassium. Hydrate of potash of potassa. Mode of 
obtaining pure hydrate of potassa. Donovan’s filtering apparatus. Uses 
of solution of potassa, and the solid hydrate. 


Fig. 90. 













244 


INORGANIC CHEMISTRY. 


that the liquid should descend freely, two conditions are required; 
first, that the air above the liquid should have the same elastic force, 
and therefore exert the same pressure as that below ; and secondly, 
as one means of securing the first condition, that the air should have 
free egress from the lower vessel. Both objects it is manifest, are here 
accomplished, since, for every drop of liquid which descends from the 
upper to the lower vessel, a corresponding portion of air passes along 
the tube, a, from the lower to the upper vessel.— Turner. 

Solution of potassa thus obtained, should be preserved in close vessels. 
It is employed in chemistry in absorbing carbonic acid gas from gaseous 
mixtures, and as a re-agent in detecting the presence of bodies, and in 
separating them from each other. The solid hydrate, owing to its strong 
affinity for water, is well fitted for freezing mixtures. 

567. Potassium inflames spontaneously in chlorine gas, and burns with 
great brilliancy, forming chloride of potassium . This chloride is also 
formed when potassium is heated in muriatic acid gas, hydrogen being 
at the same time evolved. Potassium has a stronger affinity for chlorine 
than for oxygen, as it oxides are decomposed by chlorine gas. 

Iodide of potassium is formed, with an emission of light, when the two 
elements are heated in contact. There is a Bromide of potassium formed 
by saturating hydrate of potassa with bromine. 

Hydrogen and potassium unite in two proportions, forming in the one 
case, a gray solid hydruret, and in the other, a gaseous hydruret, destitute 
of color. Thenard states, that when potassium is heated in ammoniacal 
gas, the hydrogen of ammonia is disengaged, and the potassium unites 
with the nitrogen, forming nitruret of potassium. The sulphuret of po¬ 
tassium is readily formed by the combination of the two elements by 
means of heat. It has a red color, and is very fusible. 

Potassium unites with phosphorus, forming a phosphuret. It also com¬ 
bines with cyanogen, forming a cyanide or cyanuret of potassium. 

568. Sodium. This metal, in many of its phenomena, has close 
analogies with potassium. It may be obtained by the same elec¬ 
trical and chemical processes, by acting upon pure hydrate of 
soda; but requires in its decomposition a stronger voltaic pow¬ 
er, and a higher degree of heat than is necessary to decompose 
the hydrate of potassium. The discovery of this metal is also 
due to Sir Humphrey Davy. 

It is brilliant like silver, when kept from the air; is solid at 
the common temperature, soft and ductile like wax. It is some¬ 
what heavier than potassium, its specific gravity at 59° Fahren¬ 
heit, being 0.972. It therefore nearly floats on water. It is 
less fusible than potassium ; becomes fluid at about 190° Fahr., 
but does not vaporize, except at a very high temperature. Its 
attraction for oxygen is less energetic than that of potassium. 
Its combustion with this gas does not take place till near igni¬ 
tion ; it then burns with a beautiful white flame, and bright 
scintillations, producing a yellow compound, which is a mixture 

567. Combinations of potassium with chlorine, iodine, bromine, &c. 

568. Analogies of sodium and potassium. Properties of sodium. Its 
attraction for oxygen. Combustion in oxygen. Action with water. 
Effect of air on sodium. 



SODIUM. 


245 


of the protoxide and deutoxide of sodium. It fuses on cold 
water, with a hissing noise, appearing like a globule of silver, 
and gradually melting away ; but without emitting light. On 
hot water there is an appearance of sparks and flame. In this 
combustion, the sodium unites with the oxygen, forming soda. 
Sodium tarnishes on exposure to the air, in consequence of its 
attraction for bxygen ; and like potassium, should be preserved 
in some substance in which it is insoluble, and which is free 
from, oxygen. 

569. Oxides of Sodium. There are two definite compounds of sodium 
and oxygen. 

Sodium. Oxygen. 

Protoxide 24 or one equiv. 8 or 1 equiv 

Peroxide 24 ditto. 16 or 2 ditto. 

The protoxide of sodium , or soda, is obtained by burning sodi¬ 
um in dry atmospheric air, or when sodium is oxidized by 
burning on water. It is solid, white, caustic, turns to green 
vegetable blue colors, deliquesces by attracting carbonic acid 
from the air, and becomes efflorescent. It exists in nature, only 
in combination with acids, and some metallic oxides. Like 
the protoxide of potassium, its affinity for water is such, that, at 
the highest temperature, it always retains a certain quantity; 
and can only be obtained in the state of a hydrate , in which the 
component parts are 1 equivalent of soda, 32 added to 1 water 
9=41. 

Th e peroxide of sodium, is obtained by heating sodium to red¬ 
ness in an excess, of pure oxygen. It is an orange colored sub¬ 
stance. It is resolved by water, into oxygen and sodium, and 
loses part of its oxygen by heat. 

“ Soda, (or rather the hydrate of soda,) is distinguished from 
other alkaline bases, by the following characters. 1st. It yields 
with sulphuric acid, a salt, which, by its taste and form, is easily 
recognized as Glauber’s salt, or sulphate of soda. 2nd. All its 
salts are soluble in water, and are not precipitated by any re¬ 
agent. 3d. On exposing its salts by means of platinum wire to 
the blow pipe flame, they communicate to it a rich yellow.” 
Turner. 

570. Chloride of Sodium. This union of sodium and chlorine is 
the compound so well known in all countries, as common salt. 
This substance, which exists extensively in nature in a solid 
form, as in rock-salt, and in solution in salt springs and sea-wa¬ 
ter, was formerly called muriate of soda , being regarded as a corn- 


569. Composition of its oxides. Hydrate of soda. 

570. Composition of chloride of sodium. Synonymes. Ho w proved 
to be a binary compound ? How produced. How does sea-water become 
chloride of sodium ? Chlorides of metals changed into muriates, 




246 


INORGANIC CHEMISTRY. 


pound of muriatic acid and soda. But as it may be formed by 
the direct combination of sodium and chlorine, it is evident that 
it is a binary compound consisting of a metallic base and a simple 
non-metallic element. It may be produced by heating sodium 
in chlorine gas ; the metal burns, and the result of the combust¬ 
ion is chloride of sodium. 

It may also be formed by heating sodium in muriatic acid (hydro¬ 
chloric) gas, the chlorine unites with sodium and hydrogen is liberated. 
Sea-water is muriate of soda, but by evaporation becomes chloride of so¬ 
dium ; for muriates arc changed into chlorides by heat , or by evaporation. 
Muriate of soda, for example, consists of muriatic (hydro-chloric) acid 
and soda, or the oxide of sodium; the - muriatic acid gives off its hydro¬ 
gen, and the soda its oxygen; these uniting form water, which pass off 
by evaporation, while the chlorine is left in combination with sodium. 
The muriate of potassium, in the same manner, forms chloride of potassi¬ 
um. The chloride'of metals are changed into muriates by the decompo¬ 
sition of water; the hydrogen of the water uniting with the chlorine of 
the chloride forms muriatic acid; and the oxygen of the water forms with 
the metal an oxide , and again the combination of the muriatic acid with 
this oxide constitutes a salt called a muriate or hydro-chlorate. 

571. The chloride of sodium (common salt) is transparent and 
colorless : it crystalizes in cubes. Its taste, though used as a 
standard of comparison for saline bodies, cannot be defined^ ex¬ 
cept negatively, that is, it is not sour, bitter, sweet, metallic, or 
astringent. It is grateful and agreeable ; it decrepitates at red- 
heat, and suffers igneous fusion without being decomposed. By 
an increased heat, it vaporizes in a white smoke, which conden¬ 
ses in the cold. It is remarkable for being equally soluble in 
cold, as in hot water ; it is almost insoluble in alcohol. In the 
arts salt is often used to increase the intensity of fire; this it 
does by accumulating and transmitting heat to the surrounding 
combustibles. It gives to flame a yellowish tinge. The affinity 
of Sodium for chlorine being less than that of potassium for 
chlorine whenever potassium is presented. 

572. Chloride of soda (chloride of oxide of sodium ), is formed 
when chlorine gas is passed through a solution of soda or its car¬ 
bonate. It .emits an odor of chlorine, and possesses the bleach¬ 
ing properties of that substance in a high degree. When kept 
in open vessels it is slowly decomposed by the carbonic acid of 
the atmosphere with evolution of chlorine ; and the change is 
more rapid in air charged with putrid effluvia ; because the car¬ 
bonic acid produced during putrefaction, promotes the decompo¬ 
sition, of the chloride. On this depends the efficacy of this 
chloride in purifying air loaded with putrescent exhalations. 
Chloride of soda may be employed in bleachings and for all pur- 


571. Properties of chloride of sodium. 

* 572. Chloride of soda, or disinfecting soda liquid. 



SODIUM. 


247 


poses, to which chlorine gas, or its solutions, was formerly ap¬ 
plied.”— Turner. 

573. Sodium unites with iodine and bromine ; and among the 
combustible bodies, with sulphur, phosphorus and selenium. It 
forms alloys with many of the metals. Its salts are numerous 
and important. 

Silliman remarks, “ the great prerogative of sodium is to attract oxy¬ 
gen, in which function it is only inferior to potassium. Both these re¬ 
markable bodies are endowed with such a degree of activity, and their 
chemical relations are so numerous, as almost to realize the brilliant sug¬ 
gestion of their illustrious discoverer, that they approach to the character 
of the imaginary alkahest of the ancient alchemists. Nothing can be 
more unexpected than that common «alt and sea weed should contain a 
metal, or wood ashes another. In the present state of our knowledge 
we must regard potassium and sodium as elements. As they exist abun¬ 
dantly in minerals, we can understand how in the processes of vegeta¬ 
ble life, they should become constituent parts of plants.” 

574. Lithium. This mineral is the base of a new alkali called 
lithia , discovered in 1818, by M. Arfwedson, then a young stu¬ 
dent in the laboratory of Berzelius. Its name is from the Greek, 
lithoSj a stone. It has hitherto only been found in minerals, as 
the petalite , spodumene , tourmaline , in some varieties of mica, 
and in certain waters of Bohemia. 

575. Lithia or oxide of lithium is obtained by a complicated 
process* from its mineral combinations. It is a white, caustic 
substance, changing vegetable blue colors green, and in most re¬ 
spects analogous to soda and potassa, combined with acids it 
forms neutral salts. When heated in contact with platinum it 
fuses and acts upon that metal. Its tendency to attack platinum 
is such, that, according to Berzelius, this metal can always be 
depended on to detect the presence of lithia in any mineral. 

576. Sir Humphrey Davy succeeded in decomposing lithia by 
galvanism ; but the metallic base was so rapidly oxidized, and 
thus reconverted into alkali, that it could not be collected. The 
pure metal was, however, observed sufficiently to show it to be 
of a silvery whiteness like sodium, and it burned with bright 
scintillations. 

Lithia is distinguished from potassa and soda by its power of saturat- 

* See Dictionary of chem. art. oxide of Lithium. 


573. Combinations of sodium with other simple elements, &c. Silli- 

man’s remarks. . 

574. Discovery of lithium. Derivation of the name. Where found. 

575. Properties of the oxide of lithium, or lithia. Composition of the 

oxide of lithium. .... ,. ,. . , , 

576 Lithium obtained by Davy. Properties. Lithia distinguished 
from potassa and soda. Chloride of lithium. Colored flame of the salts 
of lithia. 




248 


INORGANIC CHEMISTRY. 


ing a greater quantity of any acid. The chloride of lithium dissolves in 
alcohol, and the solution burns with a red flame. “ The salts of lithia 
when heated on platinum wire before the blow-pipe tinge the flame of a 
red color.”— Turner. 

, , -• 

# ‘ ' ' 


LECTURE XXIII. 

SECOND CLASS OF METALS. 

Order II. Metals which, with oxygen, farin'alkaline Earths. Ba¬ 
rium, Strontium, Calcium, and Magnesium. 

577. The alkaline earths differ from the fixed alkalies in being 
less soluble in water, of a. less fusible nature, and in not being 
volatile by any heat .hitherto applied. In common with the fix¬ 
ed alkalies, they are acid and caustic, give the alkaline test with 
vegetable colors, form soap with oils, and combine with acids to 
form salts. They belong to a natural class of bodies called by 
the general name of earths, and which, until recent discoveries, 
were supposed to be simple elements. 

BARIUM, 

578. This metal is little known.. It was first obtained by Sir 
Humphrey Davy. 

It is of an iron gray color, with little lustre ; it is heavier than 
water, its specific gravity being 4. It attracts oxygen from the 
atmosphere and from water, and, crumbles into a white powder, 
which is the protoxide of barium. 

The protoxide of barium, commonly called barytes .or ba¬ 
ryta was so named from the Greek, barus, ponderous, on account 
of its great specific gravity. It was discovered by Scheele in 1774. 
Baryta is obtained by the decomposition of the carbonate or ni¬ 
trate of baryta effected by means of heat. It is the sole product 
of the oxidation of barium in air or water. When heated with 
oxygen gas, it absorbs it and becomes the deutoxide of barium. 


577. How do the oxides of the metals of the 2nd. order differ from those 
of the 1st. order ? 

578. Discoverer of barium. Properties Attraction for oxygen. How 
is baryta obtained ? Its absorption of oxygen. Properties of baryta. 
Hydrate of baryta. Crystals of the hydrate of baryta. Test furnished 
by solution of baryta. 




BARIUM. 


249 


Baryta is a gray powder, possessing alkaline properties as distinct 
as those of potash and soda, except that it is less caustic and less 
soluble in water. It has a great affinity for water. When mixed 
with that liquid it slakes in the same manner as quicklime, with 
the production of more intense heat, and even light is said to be 
sometimes, evolved. The result of this process is a hydrate of 
baryta , consisting of one equivalent of baryta 78, and one of 
water 9, making its combining equivalent 87. The aqueous so¬ 
lution of baryta furnishes a valuable test of the presence of car¬ 
bonic acid, in the atmosphere, or in other gaseous mixtures. The 
carbonic acid unites with the baryta, and a white insoluble car¬ 
bonate of baryta is precipitated. 

579. Peroxide of barium , may be obtained by heating baryta, 
(the protoxide of barium,) in oxygen gas. The peroxide is of a 
greenish gray color, possessing most of the alkaline properties. 
Exposed to heat it loses a portion of oxygen and becomes a pro¬ 
toxide. All the soluble salts of baryta are poisonous. The car¬ 
bonate, which dissolves in the juices of the stomach, acts on the 
system as a poison The sulphate of barium is inert, being per¬ 
fectly insoluble. 

580. Strontium is the metallic base of strontia , an alkaline earth, 
so similar to baryta, as to have been considered the same sub¬ 
stance, until about 1791, when Dr. Hope, of Edinburgh, extract¬ 
ed what he considered as a new earth, from the strontianite , a 
mineral found in the lead mine of strontian in Argyleshire, Scot¬ 
land. Until the discovery of the alkaline metals, it was regard¬ 
ed as an elementary body. Sir Humphrey Davy first obtained 
it from the carbonate of strontia. 

581. Strontium is a heavy metal, similar to barium in appear¬ 
ance and properties. 

The protoxide of strontium , (or strontia,) exists in nature, only 
in combination with carbonic and sulphuric acids. This alka¬ 
line earth may be obtained by the decomposition of the native 
carbonate of strontia, or of the prepared nitrate. 

When mixed with water, it slakes violently like baryta, and 
produces intense heat, forming a white powder, which is the hy¬ 
drate of strontia , composed of one equivalent of strontia, and one 


579. Peroxide of barium. Salts of baryta. Chloride of barium, how 
formed ? How changed to muriate of barytes ? Bromide, iodide, &c. 

580. Of what is strontium the base ? What does strontia resemble ? 
Discovery of strontia. By whom first decomposed? 

581. Properties of strontium. Composition of the peroxide, or stron¬ 
tia. How found in nature ? How obtained ? Hydrate of strontia. Col¬ 
ored flame of strontia. Peroxide of strontium. Sulphate, carbonate, 
and nitrate. Binary compounds of strontium. Salts of strontia. What 
do they resemble ? 

22 



250 


INORGANIC CHEMISTRY. 


of water. Strontia gives to the flame of burning alcohol, a blood 
red color. The peroxide of strontium , according to Thenard, con¬ 
taining twice as much oxygen as the protoxide. It has only been 
obtained in the state of a hydrate. It may be prepared by pour¬ 
ing a solution of the protoxide, or strontia, into oxygenated wa¬ 
ter ; the hydrated peroxide precipitates in pearly scales. 

Sulphate of strontium, is found on the shores of lake Erie, at 
Detroit, and in some other parts of this continent. The carbon¬ 
ate is more rare. The artificial nitrate , is used in forming the 
blood red fire of fire-works. 

Strontium unites with chlorine, iodine, and sulphur, forming 
binary compounds. Strontia forms salts resembling the salts of 
baryta. 

582. Calcium. This metal does not exist pure in a native 
state. Its oxide, lime is very abundant, though usually com¬ 
bined with other oxides, or with acids, perfectly understood. 
Calcium is of a silvery*whiteness, heavier than water, and solid 
at the common temperature ; its affinity for oxygen is so great 
that it absorbs it from most other bodies, and oxidates or becomes 
lime in contact with air or v water. The existence of a metallic 
base in lime, had been suggested by Berzelius, before its actual 
discovery by Sir Humphrey Davy, by means of galvanic excite¬ 
ment. The process for obtaining it, is similar to that for obtain¬ 
ing barium ; substituting the protoxide of calcium, (common 
lime,) for baryta. The oxygen is evolved at the positive pole, 
and calcium appears at the negative pole. The quantities of 
this metal hitherto obtained, have been too small to afford an op¬ 
portunity for the study of its properties*. 

583. The protoxide of calcium , or lime, consists of one equiv¬ 
alent of calcium, 20, with one of oxygen, 8, making its equiva¬ 
lent number 28. Lime is extensively diffused in nature; 
it constitutes a part of the teeth and bones of animals, exists in 
many vegetable combinations, and forms a large portion of the 
rocky strata of the earth. It was formerly called calcareous 
earth. In Latin, it was called calx , a word supposed to be de- 

* Dr. Hare in 1839 was engaged in attempts to obtain calcium and ex¬ 
hibited to the author a few small silvery grains not much larger than a 
pin’s head, which he had obtained by decomposing lime. 


582. Is calcium found in nature? Properties. Affinity for oxygen. 
Existence of the metallic base of lime suggested by Berzelius. How 
was this base obtained by Davy ? 

533. Protoxide of calcium, its composition. Its existence m nature. 
Meaning of the terms calcareous, and calcinic. Modes of obtaining 
lime. Calcined lime. Its properties. Promotes the fusion of other 
bodies. 




LIME. 


251 


rived from the Arabian kalah , to burn, from which comes calcine ; 
thus, a burnt mineral, is said to be calcined. Lime is not found 
pure in nature; but is obtained by calcination of carbonate of 
lime , which exists in various forms, as limestone, chalk, marble, 
&c. For purposes of commerce, lime is obtained sufficiently 
pure, by calcining the common limestone in lime kilns. For 
use in the laboratory, powdered white marble, chalk, or shells are 
heated in a covered crucible ; the carbonic acid is expelled, and 
pure lime remains. When fully calcined, lime will not effer¬ 
vesce with acids. In its pure state, it is called quick lime . 
It is a white earthy solid, having an astringent, and alkaline taste, 
and giving the alkaline test with vegetable colors. When 
moist, it corrodes animal substances. Its specific gravity is 2.3. 
Though very infusible, it melts before the galvanic current. 
Notwithstanding its infusible nature, it is remarkable for promot¬ 
ing the fusion of other mineral bodies, and, therefore, is employ¬ 
ed in the reduction of metals. 

5S4. Lime has a great affinity for water, which when added 
to it, produces intense heat; the water, in solidifying, sets free 
a large portion of caloric, and unites with the lime, forming a 
hydrate of lime; it appears in the form of a white, bulky pow¬ 
der, consisting of one equivalent of lime, 28, with one of water, 
9, making its equivalent number 37. This well known process 
is called slaking, or slacking lime, and the hydrate is called slaked 
or slacked lime. This hydrate requires a large proportion of 
water to dissolve it, as may often have been noticed by those 
who prepare lime for white-washing walls, brick-layer’s mortar, 
&c ; and it is a singular fact, that, for this purpose, it requires 
more hot, than cold water ; thus, on heating a cold solution of 
lime-water, lime is precipitated. A hydrate of lime is formed 
when quick lime is exposed to the air ; it gradually crumbles to 
powder, as the hydrating process goes on. This air slaking chan¬ 
ges the peculiar properties of lime, while the mere water slak¬ 
ing does not; this is because the lime, in absorbing moisture 
from the air, also acquires carbonic acid, and then becomes car¬ 
bonate of lime, which is insoluble, and effervesces with acids. 

Lime-water is a solution of lime, made by mixing with it, a 
large proportion of water ; its taste is acrid, and it gives the al¬ 
kaline test with vegetable colors. It is not caustic, and contains 
so little of the earth, that it may be taken in small quantities, 
and is a valuable medicine. It must be preserved from the car¬ 
bonic acid of the atmosphere, by keeping it in well stopped bot¬ 
tles. Mixed with sweet oil, it forms an excellent liniment for 

584. Hydrate of lime, or slacked lime. Action of air upon quick 
lime. Lime water. Milk of lime. Crystals of hydrate of lime. 




252 


INORGANIC CHEMISTRY. 


burns and inflamed ulcers. The milk or cream of lime , is made 
by mixing with the hydrate, merely sufficient water to give it a 
liquid form, of the consistence of a thin paste. It is used for 
the purpose of purifying gases from carbonic acid gas ; by caus¬ 
ing them to pass through this preparation, the carbonic acid gas 
is absorbed by the lime. The simple lime water is used for the 
same purpose, though from having less of the earth in solution, 
it is less effective. Crystals of hydrate of lime may be obtained 
by placing lime-water under the exhausted receiver of an air 
pump, with sulphuric acid in another vessel. The acid having 
the property of absorbing watery vapor, facilitates the process 
of evaporation. 

585. The peroxide or deutoxide of calcium may be formed by 
passing oxygen gas over ignited lime ; it is supposed to be com¬ 
posed of one equivalent of calcium to two of oxygen. 

Chloride of Calcium. The metal calcium is too rare to be uni¬ 
ted directly with chlorine, to form the chloride ; but when pure 
lime, (protoxide of calcium,) is heated in chlorine, the latter 
unites with calcium, and oxygen is disengaged. The chloride 
of calcium is composed of one equivalent of each of its elements. 
When dissolved in water, it forms, by a new arrangement of el¬ 
ements, the muriate of lime. Muriate of lime mixed with snow, 
or pulverized ice, forms one of the most powerful freezing mix¬ 
tures. It is valuable for medicinal purposes ; and may be easily 
prepared by dissolving powdered marble in muriatic acid. 

Chloride of Lime (chloride of the oxide of calcium) is the 
combination of chlorine with lime. It possesses the bleaching, 
and other important properties of chlorine, and is, in many re¬ 
spects analogous to chloride of soda, (see § 572.) It was for¬ 
merly called oxymuriate of lime, or bleaching powder. It is pre¬ 
pared by exposing newly slaked powdered lime to an atmos¬ 
phere of chlorine gas. The chlorine combines with lime, form¬ 
ing a dry white powder, having a smell of chlorine, and a strong 
taste. Its watery solution exposed to the air, gradually disen¬ 
gages chlorine, and thus acts as a disinfecting agent. It is doubt¬ 
ful whether chloride of lime is a definite compound ;—according 
to Dr. Hare, its elements do not constitute a regular atomic com¬ 
bination. 

586. Fluoride of calcium is, according to theory, composed of 
one equivalent of calcium, 20, and one of fluorine, 10 ; this sub- 

585. Peroxide of Calcium. How is the chloride of calcium formed ? 
What change takes place when this chloride is dissolved in water ? 
Chloride of lime. How prepared ? How does it act as a disinfecting 
agent? Is it a definite compound ? 

586. Fluoride of calcium, composition, from what mineral obtained, 

&c. 



MAGNESIUM. 


253 


stance is found native, and constitutes the beautiful mineral call¬ 
ed jluor spar , which is sometimes manufactured into ornamental 
vases. Its usual color is that of a rich purple, but by exposing 
it to different degrees of temperature, artists have found means 
of forming it into a variety of beautiful colors. The finest va¬ 
rieties are obtained from the Derbyshire mines in England. The 
term jluor , was given to this mineral, because, being fusible, it 
is used as a flux for ores. 

587. We have before remarked, (see § 298) that the subject of fluo¬ 
rine and its compounds, is involved in obscurity. Since fluorine has 
never yet been obtained in a separate state, there can be no synthetic 
proof, (or proof by a direct combination of the two elements,) of the ex¬ 
istence of a fluoride of calcium, as there is by the union of chlorine and 
sodium, of a chloride of sodium. The existence of the fluoride of cal¬ 
cium is only inferred by analogy. When fluor spar is decomposed by 
hydro-sulphuric acid, the result is analogous to that obtained by the de¬ 
composition of common salt, or chloride of sodium. It is supposed that 
the hydrogen of the water in the sulphuric acid, uniting with fluorine 
of the fluoride, forms hydro-fluoric acid in the one case, and with the 
chlorine of the chloride in the other, forms hydro-chloric acid; while the 
oxygen of the water, uniting with the disengaged calcium, and sodium 
forms lime and soda; these newly formed alkalies, combining with the 
sulphuric acid, the result is, in the one case, a solid sulphate of lime, and 
in the other, a solution of sulphate of soda. The affinities which deter¬ 
mine the change, are the attraction of fluorine and chlorine for hydro¬ 
gen, of calcium and sodium, for oxygen, and of lime and soda, for sul¬ 
phuric acid. 

If lime, (oxide of calcium,) be added to hydro-fluoric acid, much heat 
ensues, the hydrogen of the acid forms water with the oxygen of the 
lime, and the fluorine and calcium uniting, form the same substance as 
fluor spar, or fluoride of calcium. This compound may be obtained by 
digesting newly precipitate carbonate of lime, in an excess of hydro-flu¬ 
oric acid. 

The iodide, bromide, sulphuret, and phosphuret of calcium, have been 
little studied, and their properties are but imperfectly known. 

The salts of lime, as the sulphate, carbonate, &c., constitute a large 
portion of the minerals of the globe, and enter into the composition of 
vegetable and animal substances. Few substances are of more general 
utility than lime; it is used in medicinal preparations; in the laboratory 
as an important re agent; in soap-making, to disengage carbonic acid 
from potash and soda; in agriculture, in building, and in various other 
arts and manufactures. 

588. Magnesium. This metal has hitherto been obtained in too 
small quantities, to afford an opportunity for extensive induction 
with respect to its nature and properties. Sir H. Davy failed in 
his attempts to procure it from magnesia, by galvanic power ; 

587. The existence of this fluoride inferred by analogy. Decomposi¬ 
tion of fluor-spar by hydro-sulphuric acid. Apparent analogies in the 
decomposition of fluor spar and common salt, by sulphuric acid and wa¬ 
ter Artificial fluor-spar. Combination of calcium with iodine, bromine, 
&c. Salts of lime. Their uses. 

588. How has magnesium been obtained ? Properties of this metal. 

22 * 



254 


INORGANIC CHEMISTRY. 


but succeeded better by subjecting solutions of the sulphate and 
nitrate of magnesia, to the action of the voltaic battery. The 
metal has since been obtained by the action of potassium on chlo¬ 
ride of magnesium, heated to redness in a tube of porcelain. In 
appearance, and many of its properties, it resembles the metals 
of the fixed alkalies, and of the metallic earths; when heated 
intensely, it burns with a vivid light, and unites with oxygen, 
forming a white oxide, or the powder called magnesia. When 
thrown into water, it gradually changes into the same white ox¬ 
ide. 

589. The oxide of magnesium , or magnesia, is composed of 
one proportion of oxygen, with one of magnesium. It was dis¬ 
tinctly remarked as a peculiar substance, by Dr Black, in 1775, 
though fifty years before its medicinal virtues had attracted at¬ 
tention. It exists in combination with acids extensively in the 
mineral kingdom, forming a component part of fa/c, soap-stone , 
serpentine , and asbestos. It exists in sea water, and in many min¬ 
eral springs. Magnesia may he obtained pure by heating the 
carbonate of magnesia, and thus expelling the carbonic acid. 
The product is called calcined magnesia ; this, in most cases, is 
preferable as a medicine, to the carbonate, because no gas is gen¬ 
erated by it in the stomach. 

Magnesia is a white, earthy powder, having neither taste nor 
odor. It gives the alkaline test with vegetable colors, though 
less strongly than the other alkaline earths. It has the essential 
character of alkalinity, that of forming neutral salts with acids. 
It absorbs water and carbonic acid from the atmosphere. It is 
a mild, harmless substance, very infusible, and insoluble. Min¬ 
erals which contain a large portion of magnesia, are very infusi¬ 
ble, as soap-stone, which is used in furnaces. 

Chloride of magnesium is obtained by passing chlorine gas over 
magnesia heated to redness; in which process, oxygen gas is 
evolved. A chloride oj magnesia is prepared by mixing a solu¬ 
tion of chloride of lime, and sulphate of magnesia ; it seems to 
possess properties analogous to those of the chlorides of soda and 
lime. 

We have now completed our examination of the two orders in the sec¬ 
ond class of metals, including all whose oxides are either fixed alkalies, 
or alkaline earths. The distinction which we have made with respect to 

589. Composition of the oxide of magnesia, &c. How does it exist 
in nature ? Calcined magnesia. Properties of magnesia. Its alkaline 
properties, &c. Hydrate of magnesia. Its sulphate soluble Infusible 
nature of magnesia. What substance promotes its fusion ? Mao-nesian 
clays useful in porcelain manufacture. Chloride of magnesium. 0 Chlo¬ 
ride of magnesia. Remarks on the division of the metals founded on 
the nature of their oxides. 





ALUMINUM. 


255 


the metals, is, perhaps, rather conventional than natural. There is a 
gradual decrease of alkalinity, from potash to magnesia, and an equal in¬ 
crease of earthy properties ; so that it might be considered as somewhat 
doubtful, whether magnesium should be classed among metals whose 
oxides are alkaline earth, or pure earths. 


LECTURE XXIV. 

METALS.—CLASS III. 

Earthy Metals; or those whose oxides are Earths. 

590. The existence of the metals of this class rests rather upon 
strong analogy, than the results of experiments. They exist in 
nature, only in the form of oxides, which are known by the gen¬ 
eral name of earths ; having neither the alkaline taste, nor giving 
the alkaline test with vegetable colors. 

591. aluminum, is the metallic base of the earth alumina , 
(alumine or pure clay.) Sir Humphry Davy failed in his at¬ 
tempts to obtain this metal by galvanic power, though he proved 
that alumina was an oxidized body; for when heated to whiteness, 
and brought into contact with the vapor of potassium, potassa 
was generated, which is an evidence that oxygen was imparted 
to the potassium by the body in contact. 

Dr. Wohler has succeeded in obtaining the metallic base of alumina, 
by heating a mixture of dry chloride of aluminum with potassium. On 
throwing the mass into water, agranular metal, resembling gun-powder 
falls to the bottom of the vessel. When the powder is rubbed on a hard 
substance with a burnisher, the particles adhere strongly, and forma sur¬ 
face which strongly reflects light, and is a conductor of electricity; 
in the state of powder, it is a non-conductor. It burns with great splen¬ 
dor, when heated in oxygen gas, and with the evolution of so much heat 
as partially to fuse the alumina, which is formed, and which is one of the 
most infusible of all substances. 

592. Oxide of Aluminum , alumine , or pure clay , is composed 
of one equivalent of aluminum 10, and one of oxygen, — 18. 

590. Evidence of the existence of these metals. Nature of their 
oxides. 

591. What is aluminum? Davy’s attempts to decompose alumina. 
How did Wohler obtain the metallic base of alumina? Describe this 
process. Properties of the metallic substance obtained. 

592. Composition of the oxide of aluminum. Its existence in nature 
Affinity for vegetable coloring mater. Origin of the name alumine. 
When first supposed to be a compound body ? 




256 


INORGANIC CHEMISTRY. 


This earth is widely diffused in nature. It is a constituent of 
every soil, and of almost every rock. It is the basis, of 
porcelain, pottery, and bricks ; and forms a part of fuller’s earth, 
ochres, pipe clays, &c. It constitutes either alone, or with other 
substances, in a crystaline form, most of the precious stones, as 
the topaz, sapphire, ruby, and garnet. Its affinity for vegetable 
coloring matter, is made use of in the preparation of lakes, for 
painting, and in dying and calico printing. Its name is from 
aluinen , the Latin name of alum , of which it is the basis It was 
considered as a simple substance, until the discovery of the alka¬ 
line metals suggested that it might be a metallic oxide. 

593. Pure alumine is seldom found in nature ; it may be obtained from 
alum, (.sulphate of alumina and potass a,) by precipitating its solution by 
a carbonate of soda or potassa ; a white bulky hydrate of alumine is thus 
obtained, which, when washed and subjected to intense heat, becomes 
anhydrous, leaving the pure alumine in the form of a white powder. It 
has neither taste nor smell, and has no effect on vegetable colors. It is 
fusible at a very strong heat forming a vitreous substance, so hard as to 
scratch glass. Though insoluble in water, pure alumina attracts it pow¬ 
erfully. Dr. Henry states, that after ignition, it attracts water so fast 
from the air, that balances show the increase of weight. It is this thirst, 
{to use a metaphorical expression,) of alumina for liquids which renders 
potter’s clay, and fuller’s earth so useful as an absorbent of oil and grease, 
when carpets, or silken, or woollen cloths are thus soiled. The alumi¬ 
nous earth in powder is laid, thickly, upon the spot, and some bibulous 
paper, (that is, coarse paper without sizing, which readily imbibes moist¬ 
ure,) placed over the powder; a warm flatiron, should be set upon the 
paper, that the oil to be withdrawn, may be kept in a fluid state, and 
thus acted upon by the absorbent earth. The paper assists in the process 
of absorption. 

After removing once or twice the saturated earth and paper, and re¬ 
placing them with other, the oily matter will be found wholly extracted. 
Spanish white, or oxide of bismuth, from its possessing the same absorb¬ 
ing property, has been found almost equally useful in similar cases. 

Though alumine is insoluble in water, it forms with it a ductile, plas¬ 
tic, cohesive and infusible paste, susceptible of being moulded into regu¬ 
lar forms, a property on which depends its use in the manufacture of 
porcelain and common pottery. But as alumine shrinks by heat, it is 
necessary that silica which does not possess this property, should be 
united with it in pottery. The natural clays often contain a sufficient 
portion of silica ; when they do not, manufacturers mix with the clay 
paste, siliceous sand or pulverized flints. Magnesia which enters into 
the composition of clays, is, from its infusible nature, and from its con¬ 
tracting but little in the fire, a valuable ingredient. But if lime exists in 


593. How may pure alumine be obtained ? Properties of pure alumine. 
Attraction for water. Absorbent properties of potter’s clay and fuller’s 
earth. Process for extracting oil by their agency. Property of alumine 
which renders it useful in porcelain manufacture. Why silica should be 
united with it in pottery. Use of magnesia with alumine in pottery. In¬ 
jurious effect of a large proportion of lime. Difference in the processes 
of glass making and pottery. Application of the contraction of clay by 
heat, to the construction of a pyrometer. 



ALUMINE. 


257 


the clay in any great proportion, it will injure the ware, by acting as a 
flux, and thus melting the vessels while baking them, destroying their 
regularity of form. Though the manufactories of glass and pottery, may 
seem to be but branches of one art, they are entirely different, while glass 
is softened by heat, and wrought at a high temperature, clay is wrought 
when cold and afterwards hardened by heat. 

The contraction of clay by heat, is so regular according to the in¬ 
crease of temperature, that Wedge wood’s pyrometer , or instrument for 
measuring high degrees of heat, has been constructed upon this property. 
Pieces of clay of certain definite dimensions, exhibit the same amount of 
contrac tion, when exposed to the same degrees of heat. 

594. Pure alumine was formerly called argil from the Latin 
argilla , pure clay ; aluminous earths, or those containing clay 
have hence been called argillaceous; and clay slate is called 



o95. Alumina appears to possess both the properties of an acid and an 
alkali. Of an acid, by uniting with alkaline bases, and of an alkali by 
uniting with acids to form salts. It is characterized by the following 
properties. 1st. It is separated from acids as a hydrate, by all the alka¬ 
line carbonates, and by ammonia. 2nd. It is precipitated by potassa or 
soda, but the precipitate is, commonly, re-dissolved by an excess of the 
alkali. 

Chloride of Aluminum , was obtained by Prof. Oersted, some years ago, 
by a direct combination of the two elements : by acting on this com¬ 
pound with an amalgam of potassium and mercury, and expelling the 
mercury by heat, he obtained a metallic substance which he believed to 
be aluminum, or the metallic base bf alumina ; and he requested Wohler 
to pursue the investigation. The latter did not succeed, until he sub¬ 
stituted pure potassium for the amalgam. (See § 591.) 

596. Zirconium. In 1824, Berzelius succeeded in decomposing 
the earth, zirconia , and obtained a peculiar substance, black like 
charcoal, which neither oxidates in the air, water, nor in any of 
the acids, except hydrofluorine, when hydrogen gas is disen¬ 
gaged. It burns intensely when heated in the open air, absorbs 
oxygen and becomes zirconia or the oxide of zirconium. Ber¬ 
zelius did not consider it a metal; it possesses some metallic 
lustre, but has not yet been proved to be a conductor of electrici¬ 
ty. It combines with sulphur, forming a chestnut brown sul- 
phuret, like that of silicon. 

The oxide of Zirconium or Zirconia is a white earth, which 
was first discovered in a mineral of Ceylon called jargoon, from 
w T hence came the name. This earth is now found in the mine¬ 
rals called hyacinth and zirconite. It resembles alumina in its 
pure white color, insolubility with water, and in being tasteless 
and without odor. 

594. Former name of clay. 

595. Derivation of the word argillite. Acid and alkaline properties of 
alumina. Two distinguishing characteristics of alumina. Chloride of 
aluminum. 

596. Decomposition of Zirconia by Berzelius. Properties of the sub¬ 
stance obtained by Berzelius by this decomposition. Oxide of Zirconium. 



258 


INORGANIC CHEMISTRY, 


597. Glucinum was obtained in 1728, by Wohler, on decom¬ 
posing the chloride of glucinum , by heating it with potassium. 
The process is similar to that for obtaining aluminum, (see § 
591.) Glucinum appears in the form of a dark gray powder, 
which by polishing, acquires a metallic lustre, and burns in the 
open air with a vivid light. Oxide of Glucinum , or glucina was 
discovered by Vauquelin in 1795 in the beryl, and by him con¬ 
sidered as a simple substance, it was at first called berillia; the 
name glucina which was afterwards given it, is from the Greek, 
glu/cosj sweet, its salts having a sweetish taste. It is found in 
the beryl, emerald, and a few other rare minerals. LikeAlumine 
it is a soft white powder, and adheres to the tongue like pure 
day. 

598. Yttrium is obtained from Yttria , a Swedish mineral of 
the earthy class ; it is distinguished from the other metals of 
those earths by a more scaly texture. Its earth, yttria resem¬ 
bles glucina, but may be distinguished from it by the purple 
color of its sulphate, and by being insoluble in potassa. The 
equivalent of yttria oxide of yttrium as stated by Berzelius and 
Thompson, is 42: if there is but one equivalent of oxygen, in 
this oxide, as is supposed, by subtracting this, viz : 8 from 42, 
34 remains as the atomic weight of yttrium. 

599. Thorinum. In 1816, Berzelius in analyzing the Swedish 
minerals which afford yttria supposed he had discovered a new 
earth, which from Thor , an ancient Scandinavian deity, he na¬ 
med thorina. But this earth, he afterwards found to be the 
phosphate of yttria. In 1828, he received from Norway, a 
black heavy mineral, now called thorite , which, on analysis, was 
found to contain a new earth resembling the substance he had 
named thorine. On account of this analogy, and perhaps to re¬ 
mind the scientific world that, if he had misnamed one substance, 
he had made ample compensation by the discovery of another to 
fill the vacancy he applied to this new mineral the exploded 
name, thorina . Thorinum the base of thorina is obtained in the 
same manner as the metals of the other pure earths by the action 
of potassium on its chloride. Its oxide , thorina is distinguished 
among the earths for its snowy whiteness. A carbonate of thor¬ 
ina is formed by heating thorina with sugar, this furnishes car- 


597. Glucinum, when obtained ? Properties. Discovery of glucina. 
Names. Where found? Properties. 

598. Discovery of yttria. Properties of yttrium and of its earthy com¬ 
pound, yttria. Equivalent of yttria, and probable atomic weight of 
yttrium. 

599. The name thorinum improperly applied by Berzelius. How is 
thorinum obtained ? Properties of thorina. How distinguished ? Car¬ 
bonate of thorinum. 




IRON. 


259 


bon, which the oxygen of the air changes to carbonic acid, and 
the latter uniting with thorina forms a carbonate. 

600. The atomic weight of the metals of the third class, is yet in a 
degree doubtful, as are also the combining proportions of their oxides. 
Neither the metals, nor their oxides, can be easily obtained in sufficient 
quantities for the purpose of thorough, and extensive experiments. 
Though aluminous earth exists every where around us, pure alumine is 
obtained but by a tedious and delicate process; and its metallic base is 
with still more difficulty set free. The other pure earths, are obtained 
from rare minerals, and their separation is attended with equal difficulty 
as that of alumina. 


LECTURE XXV. 

METALS.-CLASS IV. 

Metals whose oxides are not regarded as acids , alkalies , or earths . 

601. The first class of metals presented those which by com¬ 
bining with a large proportion of oxygen form acids ; thus we 
have arsenic acid, chromic acid, &c. The second class shew¬ 
ed us metals whose combinations with oxygen were alkalies ; as 
potash and soda. The third class exhibited metals which, by 
combining with oxygen, form insipid earths , with neither acid, 
nor alkaline properties, as alumina, &c. In these three classes, 
the metals, with few exceptions, are little known, except in the 
laboratory of the chemist; while their oxides , (by which term, 
in its most general sense, we mean combinations with oxygen, 
whether acid, alkaline, or earthy,) are, in general, familiar to all. 

In the fourth class; which we are now to consider, we shall 
find metals whose oxides are neither acids, alkalies nor earths. 
These metals have been familiar to mankind, from the earliest 
ages. From their having less affinity for oxygen, than those of 
the other three classes, they may be exposed to the air without 
oxidating. A few newly discovered metals of this class are, as 
yet, but little known. 

602. Iron. This most useful metal is, by the wise Author of 
Nature, extensively diffused over the whole earth. It is found 
in combination with most earths and stones, and it exists in vege¬ 
table and animal substances. Its ores are numerous, and exist 

600. Metals of the third class but imperfectly understood. 

601. Review of the three classes of metals examined. Metals of the 
fourth class, how. differing from the other classes ? 

602. Iron abundant in nature. Known to the ancients. Modern im¬ 
provements in its use. 





260 


INORGANIC CHEMISTRY. 


in greater quantities than those of all other metals, sometimes 
forming mountain masses. It appears to have been known to 
the Hebrews, as early as the time of Moses ; and other ancient 
nations were acquainted with its use. Its capabilities were, how¬ 
ever very imperfectly knowm. The gradual application of it to 
the various objects of human ingenuity and industry seems to 
mark the progress of the arts and sciences. The moderns only 
have applied it to the manufacture of printing presses, steam- 
engines, chain-bridges, watch springs, magnets, conductors of 
electricity, &c. &c. 

603. Iron is very infusible ; it has been melted at a heat of 
158° of Wedgewood’s pyrometer, which would be equivalent to 
2200° F. It is an excellent conductor of caloric, and softens and 
dilates when heated. It is the only metal which takes fire by 
the collision of flint. It becomes heated by percussion. Sparks 
which appear when the smith draw r s from the forge a bar of iron 
at a white heat, are burning portions of the iron. Iron will burn 
in oxygen gas, with brilliant scintillations. There is no flame 
because iron does not vaporize. 

Iron decomposes water, even at common temperatures. When 
iron filings are put into water, hydrogen gas is slowly evolved. 
Water in the state of steam, is rapidly decomposed by passing 
through iron filings in a heated gun-barrel, and for every grain in 
weight of the disengaged hydrogen, the iron gains 8 grains of 
oxygen, (see § 315.) 

604. Iron with Oxygen • There are two definite compounds of 
iron and oxygen. 

Iron . Oxygen. 

Protoxide 1 equiv. 28 added to 1 equiv. 8=36. 

Peroxide 1 ditto 28 added to 1^ ditto 12=40. 

605. Protoxide of Iron is the base of the native carbonate of 
iron , and the green vitriol of commerce. It was discovered by 
Gay Lussac, who, in heating the peroxide of iron with dry hy¬ 
drogen gas, in a porcelain tube, found that water was formed, 
and the metal had lost a portion of oxygen. Its color is dark 
blue, and when melted with vitreous substances, it gives them 
the same tint. It is less powerfully attracted by the magnet, 
than metallic iron. When exposed to the air, at common tem¬ 
peratures, it takes fire and burns vividly, absorbing oxygen, and 
burning again the peroxide. 

When metallic iron is put into diluted sulphuric or muriatic acids, hy- 

603. Effects of heat on iron. Combustion in oxygen. Decomposition 
of water by the action of iron. 

604. Composition and equivalents of the oxides of iron. 

605. Protoxide of iron. Where found in nature. Discovery. Proper¬ 
ties. How formed from metallic iron ? How may its proportion of oxy¬ 
gen be ascertained ? Affinity of its salts for oxygen. 



CHLORIDES OF IRON. 


261 


drogen is evolved, and protoxide of iron formed. Its proportion of oxy¬ 
gen may be determined by collecting and measuring the gas which is 
evolved. Its salts, particularly when in solution, absorb oxygen with 
such rapidity that they are employed in eudiometry. 

606. Peroxide of iron . In the composition of this oxide, we 
have one and a half equivalent of oxygen, with one of iron, (§ 
604,) a fact appearing at variance with the atomic theory, which 
does not admit of half an atom , and which gives 8 as the pro¬ 
portion by weight, in which oxygen unites with other bodies. 

We have formerly alluded to exceptions to this general law (§ 226.) 
According to the views there expressed, we may obviate the necessity of 
the fraction, by supposing a lower combining equivalent of oxygen, than 
has yet been admitted ; that is, calling the half equivalent, or 4, the 
atomic weight of oxygen ; this would give two equivalents of oxygen in 
the protoxide, and three in the peroxide. This would not change the 
statement of relative proportions or chemical equivalents of any of the 
combinations of oxygen. But 8 .seems, with very few exceptions to be 
the combining proportion of oxygen, and Chemists are not generally dis¬ 
posed to break up the arrangement now almost universally adopted, of 
considering the proportion of oxygen with hydrogen in water as its com¬ 
bining equivalent. 

The peroxide of iron, sometimes called red-oxide, exists in na¬ 
ture, and is known to mineralogists under the name of red- 
hcematite. The brown hcematite is a hydrate of the peroxide of 
iron : ochres are mixtures of the hydrated red-oxide and clay. 

607. The peroxide may be made by dissolving iron in nitro-muriatic acid, 
and precipitating by ammonia or other alkali, and then washing, drying 
and calcining the precipitate at a low red-heat. When fused with vitre¬ 
ous substances it imparts to them a red color. Its salts are mostly of the 
same hue. Ironrust is produced by the slow oxidation of the metal in 
the air, promoted by water, or the moisture of the atmosphere, and con¬ 
taining some carbonic acid. Black oxide of Iron. The black scales which 
appear after burning iron wire, or iron filings in oxygen gas, are a mix¬ 
ture of the blue and red oxides of iron, and in a variable proportion. 
Thus, on heating a bar of iron in the open air, the outer layer of the oxi¬ 
dated scales contains a greater proportion of the oxide than the inner; 
this is because it was more exposed to the oxygen of the air. The na¬ 
tive black oxide of iron is often found in crystals; it constitutes the 
loadstone or magnetic iron. 

“ On digesting this oxide in sulphuric acid, an olive colored solution is 
formed, containing two salts, sulphate of the peroxide and protoxide, 
which may be separated from each other by means of alcohol. These 
mixed salts, give green precipitates with alkalies, and a very deep-blue 
ink with infusion of nut-galls. The black oxide of iron is the cause of 
the dull green color of bottle glass.”— Turner. 


606. Peroxide of iron. Remarks upon its half atom of oxygen. Syn- 
onymes. Hydrate of the peroxide of iron. Ochres. 

607. How may the peroxide of iron be formed ? Properties. Coloring 
property. Iron rust. Black oxide of iron, formed by the combustion of 
iron in oxygen or air. Native black oxide, or loadstone. Salts formed 
with this oxide and sulphuric acid. 

23 



262 


INORGANIC CHEMISTRY. 


COS. Chlorides of iron were formerly called dried muriates of iron. 
The proto-chloride is obtained by dissolving the metal in diluted muriatic 
acid, and thus obtaining proto-muriate of iron ; after evaporating the so¬ 
lution, the dried mass is heated to redness in a porcelain tube from which 
the air is excluded ; and in this state it is the proto-chloride of iron. 

The perchloride may, be obtained by burning iron wire in chlorine gas. 
It is of a reddish color, and when dissolved in water, forms a red colored 
per-muriate or per -hydro-chlorate of iron. 

Iron unites with Bromine and Iodine forming a bromide , and iodide , 
and with phosphorus forming a phosphuret. The phosphate of iron (phos¬ 
phoric acid with iron) is sometimes contained In the metal, and is injuri¬ 
ous to it, by rendering it brittle at common temperatures. 

609. Carburets of Iron . Iron combines with carbon in several 
proportions ; but the most important of these combinations are 
steel and plumbago. Steel is but the sub-carburet of iron and con¬ 
tains a lower proportion of carbon than any other compound. 
The proportion of carbon in steel is very small, not generally 
exceeding one pound in one hundred and fifty. 

The experiment has been tried of enclosing small diamonds in 
the cavities of soft iron, and igniting the mass; the diamonds 
disappear, and the iron is converted into steel. This experiment 
shows that the diamond and carbon are essentially the same sub¬ 
stance ; and that it is the union of carbon with iron which forms 
steel. If a drop of any acid fall upon steel, the carbon is attract¬ 
ed by it, and a black spot appears. A drop of strong green tea 
will produce a black spot upon a steel knife. This is owing to 
the gallic acid contained in the tea. With pure iron acids do not 
produce the same effect. 

Plumbago or graphite w r as called black-lead from the common 
idea that its metallic appearance was owing to lead. The term 
is still used though, it is now known that plumbago contains no 
lead ; but consists entirely of a small portion of iron united with 
carbon, about 10 parts of the former with 90 of the latter. It is 
the percarburet of iron. It exists abundantly in nature, and may 
be formed by art, by exposing iron with charcoal to a violent and 
long continued heat. As plumbago is infusible in furnaces it is 
used for crucibles. It is much used in the manufacture of pen¬ 
cils, and is employed in iron to protect it from rust. 

610. Sulphurets of iron. The proto-sulphur et , or magnetic iron 
pyrites is of a brown color and metallic lustre. It may be ob¬ 
tained by fusing iron and sulphur together. It is much more 

608. Synonymes of chlorides of iron. Proto-chloride of iron. Per¬ 
chloride of iron. Compounds ofiron with bromine, iodine, and phosphorus. 

609. Iron with carbon. Steel. Iron changed to steel by heating with 
diamonds. Cause of the black spot produced by tea upon a steel knife. 
Plumbago. 

610. Sulphurets of iron. Properties of proto-sulphuret, &c. How ob¬ 
tained ? Localities. Deuto-sulphuret. 



SULPHURET OF IRON, 


263 


fusible than pure metal; hence if a bar of iron at a white heat, 
be rubbed with a lump of sulphur, the two substances combine, 
forming the proto-sulphuret, which melts and runs down in drops 
(§ 480.) The native proto-sulphuret of iron is found in large 
quantities, in various parts of the United States. At Stratford, 
Vermont, there is an extensive manufactory of sulphate of iron, 
{green vitriol or copperas ,) from a" mine of the proto-sulphuret 
found in its vicinity. There is a similar mine on the east side of 
the Hilderberg mountain a few miles from Albany. 

The deuto-sulphuret , is the common iron-pyrites , which exists 
in great abundance in nature. It is of a yellow color, and often 
mistaken for gold. It cannot be artificially formed. When heat¬ 
ed it loses one equivalent of sulphur, and is thus converted into 
the proto sulphuret. 

611. Though iron exists in almost every situation, pure native 
iron is seldom found. In metoric stones , magnetic iron is always 
found alloyed with nickel and cobalt, metals with which it is 
never associated in any iron ore found in the earth. This fact in¬ 
creases the interest that must be felt in these mysterious masses, 
which occasionally fall upon the earth. If, as some suppose, 
they be projected from distant volcanoes, why should they be 
unlike any other natural combinations which exist in mines or 
the bowels of the earth, as far as man has penetrated. If they 
do not belong to the earth, from whence do they originate ? Some 
say from volcanoes in the moon, others that they are formed in 
the atmosphere, and others that they are little globules, which, 
like the earth, revolve around the sun, and fall through the atmos¬ 
phere, because they come within the sphere of the earth’s attrac¬ 
tion. The iron found in these meteoric stones, is magnetic, as 
are also the cobalt and nickel combined with it. 

612. To obtain iron from its ores, for commerce, its oxides alone are re¬ 
duced. These are often combined with sulphur, arsenic, or some other 
substances which would render iron brittle. By roasting the ore, or 
subjecting it to a strong heat, these volatile substances are expelled. It 
is then mixed with charcoal and lime at a high temperature. The char¬ 
coal absorbs the oxygen of the ore, and the lime acts as a flux by com¬ 
bining with silex, clay, and other impurities, and forms a fusible com¬ 
pound called stag. The melted metal, being heavier than the slag, sinks 
to the bottom of the furnace from whence it is drawn by means of a tap 
prepared for the purpose. This is the cast-iron, of commerce ; it contains 
some carbon and un-reduced ore. By a’ further process of heating, roll¬ 
ing and hammering it is softened, and converted into malleable or wrought 
iron. 

The Latin name of iron, ferrum, gives names to some of its compounds . 

611. Pure native iron. Magnetic iron in meteoric stones. Opinions 
respecting the origin of these stones. 

612. Iron of commerce. How obtained? Cast and wrought iron. 
Latin name of iron and its compounds. 



264 


INORGANIC CHEMISTRY. 


as ferruginous earth, or earth which contains iron; ferro-cyanic acid, 
composed of iron and cyanogen, &e. 

613. Nickel. Nickel is found in nature in the state of an 
oxide , and an arseniate ; but most abundantly, as a sulphuret 
united with arsenic, a small quantity of iron, copper, and cobalt. 
It may be obtained from this compound. It is found in Chat¬ 
ham, Connecticut, associated with cobalt. 

Nickel was proved to be a peculiar metal by Bergman, in 
1775. Before that time, the ores containing it, had been sup¬ 
posed to be alloys of iron and copper. Like iron and cobalt, it is 
attracted by the magnet; and may be rendered magnetic. It is 
difficult of fusion, though highly volatile. If heated to a red heat 
in contact with the air of oxygen, it becomes an olive green 
oxide. 

It is supposed that nickel unites with oxygen in two definite 
proportions. It forms alloys with many of the metals. It has 
been remarked that meteoric stones contain nickel in combi¬ 
nation with iron and cobalt. These metallic compounds are 
remarkable for bearing exposure to the weather without rusting. 
Large masses have lain in the open air, in Siberia, Peru, and 
Louisiana, apparently for ages, with very little appearance of 
rust. 

614. Zink. This metal, sometimes called spelter , is obtained 
either from calamine (native carbonate of zink) or from zink 
blende, the native sulphuret. As it is a volatile metal, it is al¬ 
ways obtained by distillation. The zink of commerce was for¬ 
merly brought from China. It is now extensively manufactured 
in Europe. Zink is found in some parts of the United States, 
as in the Southampton, Mass , lead mines in granite and gneiss ; 
also in crystals in lime rock, near the Genesee river. It resem¬ 
bles lead in appearance, but is of a lighter color. It melts at 
about 700 Q , and crystalizes when slowly cooled. When heated 
without being exposed to the air, it sublimes, without any 
change of properties. If heated in the air, it absorbs oxygen 
rapidly, exhibiting a beautiful flame of a brilliant greenish color, 
and the newly formed oxide flies upward, in the form of white 
flowers, formerly called flowers of zink , or philosophical wool. 
When heated to a white heat, in a covered crucible placed in a 
furnace, on suddenly removing the cover, it bursts into flame 

613. Nickel, how found in nature ? When proved to be a peculiar 
metal? Properties. Aotion with heat. Combination with oxygen. 

614. From what mineral, and how is zink obtained ? Zink of com¬ 
merce, where now manufactured p Localities in the United States. 
Properties. Action of heat upon this metal. Why is zink not liable to 
rust? What property of zink prevents its extensive use for common 
purposes ? 



ZINK. 


265 


and burns with a brilliant white light. The metal may be stir¬ 
red with an iron rod to expose other portions of it to the air ; 
and then if held aloft, and poured slowly upon a brick or stone 
floor, it descends in a burning sheet, and is dashed about in a 
fiery spray. This metal is little affected by the air or moisture, 
and is therefore not liable to rust by exposure to them. On this 
account, it has been applied in the manufacture of kitchen uten¬ 
sils, and water pipes. But it is found to be attacked by fat sub¬ 
stances, especially when aided by heat; and also by the weakest 
acids ; its use is, therefore, become very limited, except in the 
laboratory. 

615. Sir H.'Davy, on observing the peculiar property of zink to resist 
corrosion, was led to make trial of it for the sheathing of vessels. Cop¬ 
per, which had hitherto been in use for that purpose, oxidizes so rapidly 
in water, as to become, in a short time, unfit for service. The copper 
was found to derive its oxygen from atmospheric air dissolved in water, 
while the oxide of copper thus formed, uniting with the muriatic acid of 
the sea water, produced a sub-muriate of the oxide of copper. If, by 
any means,- the copper could be secured against oxidation, it would not 
form a salt with muriatic acid—and according to Davy’s electro-chemi¬ 
cal theory, it only combines with oxygen because, by contact with that 
body, it is rendered electro-positive. By rendering the copper negative, 
it would then be in the same electrical state as oxygen, and the two 
would have no tendency to combine. Sir H. Davy accomplished his ob¬ 
ject of rendering copper permanently negative, by bringing in contact 
with it, zink, which when the two metals were in this state of contact, 
was positive, and the copper, consequently, of the opposite, or negative 
electricity. Thus the oxidation of the copper sheathing, was found to 
be prevented by a small piece of zink, no larger than the head of a nail, 
affixed to a sheet of 40 or 50 inches of copper. The copper was found, 
after many weeks of exposure to the action of sea water, to be perfectly 
bright, whilst the zink appeared to be slowly corroding. Triumphant as 
the success of this experiment at first appeared, it was found, on the ap¬ 
plication of it to practical purposes, to be attended with an unexpected 
embarrassment, and that, unless a certain degree of corrosion took place 
on the copper bottom of the ship, its surface became foul from the adhe¬ 
sion of sea-weeds, and shell fish. The salts of copper had in fact, served 
a useful purpose, in preventing these organic substances from fixing 
themselves in so poisonous a bed. Zink plates have been substituted in 
the place of copper ; but they are found to be liable to an accumulation 
of organic substances. A merchant in New York, sheathed the bot¬ 
tom of a ship with zink plates, fastened with zink nails but she return¬ 
ed from her voyage so exceedingly foul, that he was obliged to remove 
the zink, and substitute copper. Marine vegetables and even large oys¬ 
ters were found adhering to the zink. Thus, in the wise economy of the 
Almighty, that which cannot be decomposed for the purpose of entering 
into new combinations, is used as a matrix to multiply and support or¬ 
ganic existence. 

615. Effect of protecting the copper sheathing of ships fiom corrosion, 
by means of zink. Objections to the use of zink for the sheathing of 
ships. 

23 * 



266 


INORGANIC CHEMISTRY. 


616. The protoxide of zink is very rare in nature. It is ob¬ 
tained by the combustion of zink in the open air. Thenard sup¬ 
posed that he obtained a deutoxide , and Berzelius describes a 
peroxide , but the former was admitted by its discoverer, to have 
had but an ephemeral existence, and the latter is considered a 
form of the protoxide. 

Chloride of zink , from its soft consistence, called butter of zink, 
is formed by the combustion of zink filings in chlorine gas. It 
is of an oily appearance, very volatile and deliquescent. Wa¬ 
ter changes it to the muriate of zink. 

The natural sulphuret, called zink blende , exists extensively in 
masses, and in crystals, which are sometimes semi-transparent, 
and afford beautiful gems. The white vitriol of commerce, is the 
sulphate of zink. Zink is capable of being alloyed with many 
of the metals. Its most important alloy is with copper, consti¬ 
tuting brass ; and in other proportions, pinch-beck, Dutch gold, 
&c. Its amalgam with mercury, is used for exciting electrical 
machines. 

617. Cadmium. This metal was discovered by Stromeyer, in 
1818. During the reduction of zink ore by charcoal, the cad¬ 
mium, which is very volatile, flies off in vapor. Oxygen has 
no action upon cadmipm at the ordinary temperature, but when 

. heated in the air, it burns with a yellow flame, forming an orange 
colored oxide. It is also oxidated by nitric acid, in which it is 
more easily dissolved than in any other acid. 

Oxide of cadmium , exists in nature, combined with carbonic 
acid and silica, in calamine, and other zink ores. It may be ob¬ 
tained by heating the metal in contact with atmospheric air. 
Sulphuret of cadmium occurs native in some of the ores of zink. 
M. Stromeyer obtained it by heating sulphur and cadmium. It 
was of a beautiful orange color, and on a careful evaporation, 
crystalized in transparent, gold colored laminae. It is thought by 
mineralogists that the Missouri lead mines may afford abundance 
of both zink and cadmium. 

618. Cerium is found in a rare Swedish mineral, called cerite , 
in which it is assimilated with silica and oxide of iron. It has 
also been found with yttria in the yttro cerite. Its qualities are 
little known. There are two oxides of cerium ; The protoxide 
is a w'hite powder. When heated in open vessels, it absorbs ox¬ 
ygen, and becomes the peroxide which is of a fawn red color. 


616. Protoxide of zink. Other supposed oxides. Chloride of zink. 
Sulphuret of zink. White vitriol. Alloys of zink. Amalgam. 

617. Discovery of cadmium. Oxide. Sulphuret. 

618. Cerium and its oxides. 



LEAD. 


267 


LECTURE XXV. 

METALS OF THE FOURTH CLASS CONTINUED. 

619. Lead ■ This metal has been known from the earliest pe¬ 
riods of history. It was called by the Alchemists, Saturn ; be¬ 
cause, as this deity, according to mythological fable, devoured 
his children ; so lead, in the process of cupellation * absorbs, or 
devours most of the metals. The Latin name for lead is plum¬ 
bum. Lead is of a bluish white color, and gives a disagreeable 
odor on rubbing ; its specific gravity is 11.352. It is soft and 
flexible, and has a strong metallic lustre, when recently cut; but 
soon tarnishes, on exposure to the air. It is one of the most fu¬ 
sible of the metals ; melting much below red heat; it crystali- 
zes on cooling. Atmospheric air, and dry oxygen gas, have no 
action upon it ; but when moist, they soon tarnish it, covering 
it with a gray coat of the protoxide of lead. When fused in 
open vessels, a gray film is formed on its surface, which is a mix¬ 
ture of metallic lead and the protoxide ; and when strongly heat¬ 
ed, it volatilizes in fumes of the yellow oxide of lead. 

On account of its abundance, and the facility with which it is 
wrought, lead is much employed in the arts. It is extensively 
used for aqueducts, reservoirs, chambers for the manufacture of 
sulphuric acid, printing types, and covering and sheathing gutters, 
and roofs of buildings. It is employed in medicine. Many of 
its compounds are poisonous to the human system. 

It has been asserted that leaden pipes for conducting water are unsafe 
on account of the supposed danger of the water becoming impregnated 
with the metal and thus operating as a poison. Dr. Turner considers 
that the salts in spring water, by gradually forming an insoluble film on 
the metallic surface of leaden pipes, effectually secure it against any 
change which would cause it to re-act upon the water. Lead is acted 
upon by the acids which also when present promote the absorption of ox¬ 
ygen and carbonic acid from the" atmosphere. Vinegar contains acetic 

*The oxides of lead have the property of combining with most of the 
metals, except gold, silver, and platinum, and on this account are used 
for purifiers, by a process called cupella,tion , a term derived from cupel , 
the name of a peculiar kind of vessel used in the operation. In this 
process, the lead melts first, and carries with it, in fusion, all the baser 
metals. 

619. Alchymistical name of lead. Latin name. Properties. Action 
with heat, dry air and oxygen. Effect of moisture combined with air 
or oxygen. Effects of fusing, and heating in open vessels. Various 
uses of lead. Action of acids upon lead. 



26S 


INORGANIC CHEMISTRY. 


acid ; and pickles should not, therefore, be kept in pots of earthen ware 
which are glazed with lead, as the acid corrodes the lead and forms pois¬ 
onous salts. Stone ware is not liable to the same danger. 

620. Protoxide of lead , exists in nature only in combination with 
acids forming salts. It is prepared in laboratories, by decompo¬ 
sing any salt of lead by potassa or soda. When first precipita¬ 
ted, it is white because it contains water or is hydrated, but 
when dried by heat and air it becomes yellow. This, in com¬ 
merce, is called massicot. When the protoxide is partly fused in 
the air, it unites with about 4 per cent of carbon, and is called 
litharge; The protoxide" forms with acids all the salts of lead, 
most of which are white. It readily unites with earthy bodies 
when fused with them, forming the lead glazing for pottery, flint 
glass , and pastes for artificial gems. The protoxide of lead in¬ 
creases the refractive and dispersive power of glass more than any 
substance, so that the gems made with it resemble the diamond, 
but may easily be distinguished by their inferior brilliancy and 
hardness. 

621. Deutoxide of lead is formed by heating litharge, or the pro¬ 
toxide, in open vessels with free access of air. This is known 
in commerce as minium or red lead. It is used in potteries for 
glazing, in the manufacture of flint glass, and as a paint for oil 
colors. It is also used for the coloring of red wafers which are 
consequently poisonous. 

Peroxide or tritoxide of lead is obtained by digesting the deut¬ 
oxide in nitric acid, which dissolves one part, leaving the other 
combined with a large portion of oxygen. This oxide is of a 
brown color, called puce or pea colored. It is not used in the 
arts, or in medicine. 

Fixed vegetable oils, if heated with the oxides of lead, dis¬ 
solve a portion of them, and are converted into what is called 
drying oil. 

622. Chloride of Lead may be obtained by the action of chlo¬ 
rine gas on thin plates of lead. It is soluble in hot water, and is 
then considered a muriate of lead. A compound of the chloride 
and protoxide of lead forms the paint called patent yellow. The 
sulphuret of lead exists abundantly as a natural ore, called galena. 
This is the only one which is wrought for the purpose of extract- 

620. Protoxide of lead. Massicot. Litharge. Union of the protox¬ 
ide with acids, and with earths. Use of the protoxide of lead in glass 
artificial gems. 

621. Deutoxide of lead. Red lead. Its uses. Peroxide of lead. Dry¬ 
ing oil. 

622. Chloride of lead. Muriate of lead. Patent yellow. Sulphuret 
of lead or galena. Lead mines of the United States. Silver obtained 
from lead ore by cupellation. 



SULPHURET OF LEAD. 


269 


ing lead. It is found in masses, and in cubic and octahedral chrys- 
tals. It is usually associated with the sulphurets of antimony, 
bismuth and silver. Galena is called potter's lead ore , because it 
is used in pottery for glazing. This ore is abundant in the 
United States. The Missouri lead mines are remarkable for 
their richness. 

There is a lead mine of considerable extent in Southampton, Mass. 
From specimens of galena found in that locality, we should in¬ 
fer that it might hereafter prove very valuable when improved 
processes for carrying on mining operations, and reducing metals, shall 
be better understood in this country.* 

The proportion of silver in lead ore is judged of by cupella- 
tion; a small piece of metallic lead is heated under a muffle, 
upon a cup of ashes made by burning bones. The lead ox¬ 
idizes, the oxide is absorbed by the ashes, and a button of silver 
remains. 

623. Lead forms various alloys ; among the most important, 
is that with antimony for printing types. The antimony is usu¬ 
ally in the proportion of 1 to 3 or 4 of lead; its principal use is in 
hardening the lead. With tin, lead forms alloys of different 
kinds; as pewter ^ in which tin constitutes more than half the 
compound ; organ pipes, tin foil, and nails used for some pur¬ 
poses in ship-building, because they do not rust in saltwater. 
The solder of the tinner is composed of lead and tin. A com¬ 
pound of lead, tin and bismuth, melts below 212 Q , so that spoons 
made from it melt in boiling water. 

Lead is precipitated from its acid solutions both by iron and zink. 
Th e lead tree (or arbor saturni)\ exhibits a beautiful arborescent crys- 
talization of pure metallic lead, precipitated by means of zink. A small 

* In 1821, the author received from Charles Bates, Esq. some remark¬ 
ably fine specimines of galena from the Southampton lead mine, and was 
informed that the working of the mine had been attempted, but after¬ 
wards relinquished on account of the difficulty and expense attending it. 

t Tree of Saturn. 


623. Alloys of lead. Lead tree. How formed, Theory of the lead tree. 



270 


INORGANIC CHEMISTRY. 


bunch ot clean zink is sus¬ 
pended by a thread from the 
stopper of a transparent 
glass bottle, containing an 
ounce of the acetate of lead 
(sugar of lead,) dissolved in 
a pint and a half of water. 
The lead is gradually pre¬ 
cipitated upon the zink, 
shooting forth into brilliant 
crystaline branches. The 
tree will continue to in¬ 
crease during several days 
if the solution be suffered to 
stand undisturbed,and forms 
a beautiful and scientific or¬ 
nament for a mantel piece. 
The precipitation of the lead 
is, at first, a chemical phe¬ 
nomenon. The zink attracts the acetic acid from the solution of acetate 
of lead, and the lead is set free. The precipitation of the lead upon the 
zink is supposed to be caused by galvanic influence. The two metals 
represent the two poles of the voltaic apparatus, and the presence of di¬ 
luted acid develpping the electrical agencies, a mutual attraction be¬ 
tween the metals ensues. 

624. Copper. This metal is said to have been discovered in 
the isle of Cyprus and dedicated in heathen mythology, to the 
worship of Venus ; hence the alchemists termed this metal Ve¬ 
nus. The Latin name copper or cuprum , is derived from Cy¬ 
prus. The implements of war, and domestic utensils of the an¬ 
cients were mostly made of bronze, or some other alloy of cop¬ 
per and tin. Copper is found pure in native masses and crys¬ 
tals, also in the state of sulphuret, carbonate, oxide, sulphate, 
arseniate, and phosphate. Copper is the only metal except ti¬ 
tanium which is of a red color ; it is very malleable, ductile, and 
elastic, and is the most sonorous of the metals. When rubbed, 
it emits a peculiar, nauseous odor. The pure metal and its com¬ 
pounds are all poisonous. It fuses at a white heat, and if the 
heat is urged further, it volatizes in visible fumes. On cooling 
slowly, it crystalizes in quadrangular pyramids. Copper filings 
thrown into a strong fire, burns with a green flame. It dobs not 
strike fire with flints, and is therefore used for the nails, ham¬ 
mers and other implements used in the manufacture of gunpow¬ 
der. But when exposed to the compound Blow pipe it burns 


Fig. 91. 



624. Origin of the name copper. This metal known to the an¬ 
cients. Ilow found in nature^ Color and other properties of copper. 
Action with heat. Why copper nails and hammers used in operations 
connected with the manufacture of gun powder. Combustion of cop¬ 
per. Color of the flame. Formation of sub-carbonate of copper. Cop¬ 
per vessels for culinary purposes. Oxidation of copper. 



















COPPER. 


271 


with a green flame and light too intense for the eye. On ac¬ 
count of the color of its flame the salts of copper are sometimes 
used in artificial fire works. 

Copper is little changed by a dry atmosphere ; but when ex¬ 
posed to air and moisture, it becomes thinly coated with a green 
sub-carbonate. As this metal is poisonous, culinary vessels of 
copper should never be used except when perfectly clean, or 
well tinned. When heated to redness, copper oxidizes, and be¬ 
comes covered with brown scales. 

625. Oxides of Copper. There are two definite combinations 
of oxygen and copper both which unite with acids to form salts ; 
they are thus constituted. 

Copper. Oxygen. 

Protoxide 64, 8=72. 

Peroxide 64, 16=80. 

626. The protoxide of copper being regarded as composed of 
one equivalent of each element and oxygen, the latter constitut¬ 
ing 8 parts in 72, it follows that the atomic weight of copper is 
64. The red protoxide of copper may be obtained by igniting 
in a close vessel 64 parts metallic copper with 80 parts of the 
peroxide, the metal takes from the peroxide one portion of ox¬ 
ygen, and the latter is thus reduced to the protoxide, of which, 
as 64 added to S0=144, there are 144 parts. The protoxide of 
copper is dissolved by some of the acids, as also by ammonia ; 
in solution with the latter it is colorless: but, on exposure to 
the air, it becomes blue, owing to the formation of the peroxide. 
The salts of the protoxide rapidly absorbs oxygen from the air, 
and become per-salts ; that is, the base of the salt changes from 
the protoxide to the peroxide, and the salt is, in consequence, 
changed from a proto-salt to a per-salt. The protoxide exists in 
nature ; beautiful crystals of it are found in the mines of Corn¬ 
wall, and in Connecticut and New Jersey. 

627. Peroxide , or black oxide of copper, is formed by expos¬ 
ing the metal, for some time, to red heat, in the open air. The 
peroxide of copper is insoluble in water : it does not give the 
alkaline test with blue vegetable color, but unites acids to form 
salts ; these salts are either green or blue. With ammonia, it 


625. Oxides of copper. 

626. Composition of the protoxide of copper. How is the atomic 
weight of copper known ? How is the protoxide of copper obtained ? 
Action of the acids and ammonia on the protoxide of copper. Salts of 
the protoxide. Existence of the protoxide of copper in nature. 

627. Manner in which the peroxide of copper is formed. Properties. 
Action with ammonia. With potassa and albumen. 



272 


INORGANIC CHEMISTRY. 


forms a deep blue solution, a property which is peculiar to the 
peroxide of copper, and which affords a valuable test. It is pre¬ 
cipitated of a yellowish white color, by albumen, so that the 
white of eggs, and other substances containing albumen, are an 
antidote to the poison of this salt of copper. 

628. The proto-chloride of copper may be prepared by heating 
copper filings with twice their weight of per-chloride of mer¬ 
cury, (corrosive sublimate.) The perchloride may be obtained 
by digesting the proto-chloride in muriatic acid, and exposing the 
permuriate of copper, which is thus formed to a temperature of 
about 400° F. It is deliquescent in the open air, and becomes 
again the permuriate, by absorbing moisture, thus changing from 
white to green. 

Sulphuret of copper is a constituent of variegated copper ore- 
It may be prepared by fusing copper and sulphur together. 

Bi-sulphuret is of a yellow color, and more common as a na¬ 
tive production, than the sulphuret. It exists in copper pyrites 
combined with proto-sulphuret of iron. 

The alloys of copper are numerous ; that with zink , forming 
brass * is perhaps the most important. With fin, copper forms 
bronze, cannon metal, bell metal, and coating for the interior of 
copper vessels, and metallic mirrors. With gold or silver, it 
forms coin, and gold and silver ornaments. Zink, tin, and es¬ 
pecially iron, precipitate copper from its solutions. A knife 
blade, on being immersed in a solution of copper, is instantly 
covered with the metal. Nitric add acts forcibly upon copper, 
yielding to it one equivalent of oxygen, to form the protoxide of 
copper, and evolving the deutoxide of nitrogen, and nitrous acid 
gas, (see § 354.) The blue paint, verditer , is the hydrate of cop¬ 
per with a little lime. Native copper exists iu various parts of 
the United States. According to Silliman, it has been found 
near New Haven, Connecticut, and near lake Superior, and oth¬ 
er localities in that region. The copper of commerce is usually 
obtained from the sulphurets. 

629. Bismuth. The name is supposed to be a corruption ot the 
German Weissmuth, or white mother of silver. It was former- 

* The manufacture of brass has been practised from remote ages. 
The ancients confounded copper, brass, and bronze. Brass was, in their 
view, only a more valuable kind of copper, and they often used the word 
as, to denote either. 


628. Chlorides of copper. Proto-chloride. Per-chloride. Sulphuret 
of copper. Bi-sulphuret. Alloys of copper. Metals which precipi¬ 
tate copper from its solutions. Action of nitric acid with copper. Ver 
diter, &c. Native copper. Copper of commerce.' 

629. Origin of the name bismuth. Properties. Oxide of bismuth. 




BISMUTH.. 


273 


ly called glazed tin. It is brilliant, of a yellowish white color, 
and very brittle. It is very fusible. At a high heat, and in 
close vessels, it may be completely volatilized. When melted 
in the air, its surface becomes covered with a greenish brown 
oxide. Oxide of bismuth may be obtained by burning bismuth 
in the open air, and collecting the fumes. The yellow oxide 
which is thus obtained, was formerly called flowers of bismuth. 
The oxide of bismuth has been computed to contain 72 parts of 
bismuth, and 8 of oxygen, one equivalent of each element, the 
equivalent of the oxide is, therefore, 72 added to 8—80. When 
the nitrate of bismuth is mixed with water, a precipitate is form¬ 
ed of the sub-nitrate, known as the pearl white , (or blanc de 
fardj) of perfumers ; from its pearly whiteness it is used as a 
cosmetic. It is injurious to the skin, and is also liable to assume 
a tawny hue, in contact with sulphuretted or phosphuretted hy¬ 
drogen ; thus, the effluvia from boiled eggs, and some mineral 
springs, and even sitting before a fire of mineral coal, may 
change a brilliant artificial white complexion, into a mulatto 
color. 

When the powder of bismuth is heated with chlorine gas, a 
pale blue light appears, and a white chloride of bismuth is form¬ 
ed, which from its oily appearance, was formerly called butter of 
bismuth. 

Bismuth is found in the earth in the form of pure ore, of an 
oxide, a sulphuret, and an arseniate. The only known Ameri¬ 
can locality of native bismuth, is at Monroe, Connecticut, 17 
miles west of New Haven. 

630. Mercury. So named by the Alchymists from the planet 
Mercury. Its common name is quicksilver. Its discovery is of 
high antiquity. The Alchymists imagined it was liquid silver, 
and that by solidifying, it would form that metal. The Latin 
name, hydrargyrum , from the Greek udor, water, and argenon , 
silver, denotes that it was supposed to be liquid silver. Boer- 
haave is said to have held it in digestion twelve years, in order 
to obtain a solid precipitate of silver. The Alchymists, howev¬ 
er, in their vain attempts to change mercury into silver, discov¬ 
ered many important preparations, which are of great use in 
medicine, and in the arts. 

Mercury is the only metal that is fluid at the common tem¬ 
perature of our climate. At 40° below zero, F., a cold which 
sometimes prevails in the polar regions, mercury becomes solid, 
and forms octahedral crystals. It can also be congealed by arti- 

630. Origin of the name mercury. Common name, &c. Opinion of 
the Alchymists, &c. Mercury in a solid state.. Properties of fluid mer¬ 
cury. 


24 




274 


INORGANIC CHEMISTRY. 


ficial means. In a solid state, it is malleable, and may be cut 
■with a knife ; applied to the skin, it produces a sensation no less 
painful than that of red hot iron. If a small quantity of solidi¬ 
fied mercury be thrown into a glass of water, it melts, while the 
water is frozen by the loss of its latent heat, and the glass is 
shivered to pieces. Mercury in its fluid state, possesses perfect 
mobility, it is white and brilliant, like polished silver. The 
clean surface of a vessel of mercury, is a most perfect and splen¬ 
did mirror. 

631. On account of its great weight, it affords the most per¬ 
fect means of demonstrating the statistical and moving force of 
fluids and caloric, is essential in the construction of the bardme- 
ter, and forms the most useful thermometer. The mercurial 
cistern for collecting gases, has proved of great importance in 
chemical experiments. 

The specific gravity of mercury at 47 Q F., is 13.568. It con¬ 
tracts in congealing, so that its specific gravity is increased to 
15.612; thus, frozen mercury sinks in the fluid metal. The 
boiling point of mercury seems to be about 650°, or a little more 
than three times the heat of boiling water. Its vapor conden¬ 
ses on cool surfaces, in minute metallic globules. The usual 
method of purifying mercury, is by distillation. Its vapor is 
very expansive, having a specific gravity of 6 97, air being con¬ 
sidered as unity, or 1. If mercury be heated in strong iron ves¬ 
sels, closely covered, the force of its expansion will burst the 
vessels. Mr. Faraday proved that mercury volatilizes slightly, 
without the application of heat. By exposing gold leaf for some 
time over a vessel of mercury, he found the gold leaf whitened. 

632. Mercury, at the common temperature, is not tarnished 
by atmospheric air or oxygen gas ; but at a boiling heat, it grad¬ 
ually becomes a red oxide. Sulphuric and nitrous acids, act 
upon mercury. The former has no action upon it in the cold ; 
but on the application of heat, the mercury absorbs a portion of 
oxygen from the acid, sulphurous acid is disengaged, and a sul¬ 
phate of mercury formed. Nitric acid, without the aid of heat, 
oxidizes and dissolves mercury, with a disengagement of the 
deutoxide of nitrogen. 

Oxides of mercury were formerly called mercurial calcs.* 

* Metallic calces,* (from calx,) were metals which had undergone the 
process of calcination or combustion, or some equivalent operation. 


331. Uses of mercury. Specific gravity of mercury. Boiling point. 
Vapor of mercury. Volatilization of mercury without heat. 

632. Oxidation of mercury. Oxides of mercury. Protoxide. Pe¬ 
roxide, mode of obtaining it. Thenard’s theory of this process. De¬ 
composition of the peroxide by heat. 





MERCURY. 


275 


There are two compounds of oxygen, and both of the resulting 
oxides form salts with acids ; they are constituted as follows : 

Mercury. Oxygen. 

Protoxide 200, or 1 equiv. 8=208. 

Peroxide 200, “ 16=216. 

Protoxide , or black oxide of mercury , is formed when mercury 
is violently agitated, for a long time, in contact with the atmos¬ 
phere. 

Peroxide , or red oxide may be obtained by exposing the metal 
to heat in the open air. 

The peroxide of mercury may also be obtained by the following pro¬ 
cess. Mercury is dissolved in nitric acid, and the nitrate so formed is 
exposed to heat, red fumes are given off, and the peroxide of a beautiful 
red color appears. The theory of this change, is thus explained by 
Thenard.* The nitrate of mercury used in this process, is a mixture of 
the nitrates of protoxide and deutoxide, (peroxide,) of mercury; when 
exposed to nearly red head, the nitric acid changes to oxygen, and ni¬ 
trous acid gas ; the latter, not being retained by the oxide of mercury, 
is disengaged in the form of red fumes; the oxide, now changed by an¬ 
other proportion of oxygen to the deutoxide (or peroxide,) of mercury, 
remains in the form of deep red scales, called red precipitate. When 
heat will disengage no more nitrous acid, (which acid is easily known by 
its color and peculiar odor,) the operation is completed, and the perox¬ 
ide is to be preserved in closely stopped bottles. When heated to red¬ 
ness, it is converted into metallic mercury and oxygen, in the propor¬ 
tion of 16 parts of the latter, to 200 of the former. The peroxide is 
much employed in medicine. 

633. Chlorides of mercury. Their compounds are as follows : 


Mercury. 

Proto-chlorine 200 
Bi-chloride 200 


Chlorine. 

36=236. 

72=272. 


The proto-chloride of mercury is calomel, formerly called 
white precipitate of mercury. It may be formed by exposing the 
metal to chlorine gas, at common temperatures ; also by adding 

* Traite de Chirnie , Tome II. p. 392. Most elementary writers on 
Chemistry, state the process for obtaining the peroxide of mercury from 
the nitrate, without attempting any theoretical explanation. Silliman, 
(Elements Vol. II. p. 314 and 315.) considers “ the nitrate as a compound 
of peroxide and per-nitrate.” This he says is decomposed by heat, till 
all the fumes cease, and then (page 307) “the oxide will become of a 
beautiful red color.” He does not state the nature of the decomposi¬ 
tion which takes place; nor how, by means of it, the whole remaining 
mass is brought to the state of a peroxide. 

633. Chlorides of mercury. Formation and properties of calomel, or 
the proto-chloride of mercury. Per-chloride of mercury. Difference 
in the constitution of corrosive sublimate and calomel. Properties of 
corrosive sublimate. Antidotes. Mode of obtaining the per-chloride 
&c. Tests of corrosive sublimate. 





276 


INORGANIC CHEMISTRY. 


to a solution of common salt or muriatic acid, a solution of mer¬ 
cury in nitric acid. A white heavy powder is precipitated, it is 
tasteless, and insoluble in water, and sublimes by heat without 
decomposing. 

Bi-chloride or per-chloride. This is the active poison, known 
under the name of corrosive sublimate. In constitution, it differs 
from calomel only in one additional equivalent of oxygen ; and 
yet its properties are widely different. Its taste is highly acrid 
and burning ; it is corrosive to animal substances, and a strong 
poison. It unites with albumen, which, by attracting one 
equivalent of chlorine, changes it to the proto-chloride of mer¬ 
cury, (or calomel.) The white of eggs, which are chiefly al¬ 
bumen, are therefore, if taken in season, an antidote to this poi¬ 
son. A solution of pearlashes, by decomposing corrosive subli¬ 
mate, answers a similar purpose. The per-chloride of mercury 
may be obtained by heating the metal in chlorine gas, or by 
heating sulphate of mercury. 

The presence of mercury in any fluid supposed to be poisoned 
with corrosive sublimate, may be discovered by various tests ; 
with sulphuretted hydrogen, it will cause a black precipitate, 
which is the sulphuret of mercury. Nitrate of silver will pro¬ 
duce a white precipitate, the chloride of silver and alkalies, pro¬ 
duce a yellow precipitate. 

634. Bi-cyanuret of mercury is composed of one equivalent of 
mercury, 200 added to 2 cyanogen 52=252. It is sometimes 
called the cyanide , or cyanuret of mercury. Its common name is 
prussiate of mercury. 

It is obtained by boiling with a portion of water, red oxide of mercury, 
with twice its weight of prussian blue, (the ferro cyanate of peroxide of 
iron,) until the blue color of the latter disappears. The colorless solution 
of the bi-cyanuret of mercury which is formed, crystalizes in four sided 
prisms, when carefully evaporated. The theory of the process is this, 
the oxygen of the oxide of mercury unites with the iron and hydrogen of 
the ferro cyanic acid ; while the metallic mercury, and cyanogen, being 
both disengaged, enter into combination. The peroxide of iron remains 
in the form of a brown, insoluble mass. When heated in close vessels, 
the bi-cyanuret decomposes ipto metallic mercury and Cyanogen. It has 
a disagreeable, metallic taste, and is very poisonous. When heated with 
one third of sulphur, one part of the cyanogen is disengaged, and a sul- 
pho-cyanuret of mercury is formed. Most of the hydracids decompose 
it, forming hydro-cyanic, (prussic acid,) which is disengaged, and a 
chloride, iodide, bromide, &c. 

635. Sulphurets of mercury. The pro-sulphuret is black. It 
was formerly called Ethioph mineral. It may be prepared by ad¬ 
ding to melted sulphur, its own weight of mercury. The bi- 

634. Composition of the bi-cyanuret of mercury. Synonymes. How 
obtained? Theory of the process. 

635. Sulphurets of mercury. 




MERCURY. 


277 


sulphuret , deuto , or per-sulphuret , is the cinnabar , or vermillion 
of commerce. It is very valuable in the arts as a paint. It is 
found in nature, and by its decomposition, affords most of the 
mercury of commerce. By mixing with iron filings, and heating 
the mixture, the sulphur passes to the iron, and the mercury is 
obtained by sublimation. The two sulphurets are composed of 
mercury and sulphur, in the proportions of 1 and 2 equivalents 
of sulphur, to 1 of mercury. Native cinnabar is usually found 
in secondary geological formations. 

636. Alloys of mercury with other metals, are called amalgams . 
The affinities of metals for mercury differ. Some, as gold, sil¬ 
ver, and tin, form amalgams with mercury, by mere contact; 
but in most cases, the fusion of the solid metal is necessary. 
Heat decomposes amalgams by volatizing the mercury. Some 
amalgams, as those of potassium and sodium, decompose at the 
common temperatures. The amalgam of tin and mercury, is 
fluid at a low heat, which facilitates its use as a coating for glass, 
to form mirrors. This process is called silvering ; the mercury 
being poured upon a sheet of tin foil, the glass plate is pressed 
upon it with a weight, for a day or two, and the amalgam will 
be found adhering to the glass, merely from the force of attract¬ 
ion. Articles of gold and silver, when exposed to mercury, lose 
their peculiar lustre ; the gold becomes white like tarnished 
silver, and the silver assumes the dusky hue of old pewter.* 

Mercury is found in Hungary, Spain, Italy, South America, 
and the East, and West Indies. It exists in small quantities in 
Great Britain and France. It is found sparingly in the pure me¬ 
tallic form. The most abundant of its ores, is the native cinna¬ 
bar, or bi-sulphuret; this is usually red, or of a reddish gray 
color, and is the only one which is wrought for the metal. The 
presence of mercury in ores may be easily ascertained, as it vola¬ 
tilizes before the blow pipe ; and if heated with quick-lime in a 
retort, the metal sublimes in the form of small globules. 

* Some years since the author was invited by Prof Silliman, (no less 
distinguished for urbanity than for scientific attainments,) to examine the 
extensive laboratory of Yale College. He showed with much satisfac¬ 
tion, a fine mercurial cistern, the largest as he stated, in the United 
States. His visiter being then unacquainted with the amalgamating 
nature of mercury, and encouraged by the Professor’s example, was 
about to thrust her hand into the mercurial liquid, when he exclaimed 
with earnestness, “ take pare of your rings,” and thus saved her from 
the chagrin of seeing her “ fine gold become dim.” 


636. Alloys of mercury. Process of forming glass mirrors. * Change 
of gold and silver with mercury. Localities Of mercury. Native com¬ 
binations of mercury. Test for the presence of mercury in ores. 

24 * 



278 


INORGANIC CHEMISTRY. 


LECTURE XXVII. 

FOURTH CLASS OF METALS CONTINUED. 

637. Silver. The Alchymists called this metal Diana or Luna, 
(the moon,) probably on accouut of its white lustre. In refer¬ 
ence to this name, the nitrate of silver is called lunar caustic. 
The Latin name was argentum ; thus argentine is a term often ap¬ 
plied to compounds of silver. Silver and gold are called the 
precious metals, both on account of their superior brilliancy, and 
their use as coin throughout the civilized world. Silver is of a 
brilliant wdiite color, more malleable and ductile than any metal 
except gold. It may be extended into leaves not exceeding the 
1-10,000 part of an inch, and drawn into wire finer than a hu¬ 
man hair. Its specific gravity is 10.39. It is so soft, that it may 
be cut with a knife. It may be volatilized by a very strong heat 
continued for some time. It is not oxidated by the air, or by the 
heat of a furnace ; but may be burnt by passing a powerful gal¬ 
vanic shock through its fine wire. It then gives out a beautiful 
light green flame, and combines with oxygen, forming the oxide 
of silver. The silver of commerce always contains a-small alloy 
of copper, in which state it is wrought by the silversmith. 

638. Though silver is not easily affected by oxygen, it tarnish¬ 
es in contact with sulphur and sulphurous compounds. Hence 
the dark color imparted to silver spoons by boiled eggs, the 
whites of which contain some sulphur. Nitric and sulphuric 
acids, oxidate this metal, forming with it lunar caustic, nitrate of 
silver, and sulphate of silver. 

639. - Silver is often found pure in a native state, frequently sul¬ 
phuretted, often alloyed with other metals, such as gold, an¬ 
timony, copper and arsenic, and sometimes blended with sul- 
phuret of lead, and copper pyrites. In Mexico and some other 
countries, it only needs melting to obtain it pure. Silver is 
extracted from lead ores by cupellation , and from ores where lead 
is not present by amalgamation. There is some silver in the 
lead ores found in various parts of the United States; but no 
silver mines have, yet been discovered. The Andes of South 

637. Names of silver and its combinations. Precious metals. Prop¬ 
erties of silver. Combustion of silver by means of galvanism. Silver of 
commerce. 

638. Action of sulphur upon silver. Action of nitric and sulphuric 
acids, 

639. Silver as existing in nature, and native combinations. Extraction 
of silver from ores. Localities of metallic silver. 



SILVER. 


279 


America, an4 the Codilleras of Mexico are very rich in native 
metallic silver. 

640. Oxide of Silver may be obtained by precipitating a so¬ 
lution of the nitrate of silver by potassa or soda. It is of an olive 
green color, and insoluble in water. When heated to redness, 
the oxygen is exploded, and the metal revived. There is but 
one oxide of silver composed of one equivalent of silver and one 
of oxygen, and therefore considered the protoxide of silver. 

Silver, when in solution with nitric, or sulphuric acid, is pre¬ 
cipitated in the metallic state by copper and mercury ; it then 
assumes an arborescent appearance called the silver tree or arbor 
Dianse. A globule of silver put into a white glass vessel, with 
a dilute solution of lunar caustic, (nitrate of silver,) and suffered 
to remain undisturbed, will, in a few days, exhibit this brilliant 
and beautiful tree. On immersing a bright copper cent, or rod, 
in a solution of the nitrate, it will be covered with white crystals. 

641. Fulminating Silver , or ammoniuret of Silver, is a very dangerous 
preparation, exploding by blood heat, or by the slightest touch. It is 
formed by adding strong liquid ammonia to oxide of silver ; a black pow¬ 
der is precipitated; this was supposed by Berthollet, its discoverer, to be 
a compound of ammonia, and oxide of silver. The products of its detona¬ 
tion are metallic silver, water, and nitrogen gas. The phenomenon of 
detonation is ascribed to the action of the oxygen upon the hydrogen of 
the ammonia, forming steam, which is suddenly exploded, along with the 
nitrogen and metallic silver. 

The detonating silver first prepared by M. Descotils is made by dis¬ 
solving silver in a small quantity of nitric acid, and heating the solution 
with an equal bulk of alcohol; on cooling,a crystalline powder falls, 
which must be washed, and dried on blotting paper. M. Liebig and 
Gay Lussac consider the fulminating and detonating compounds, to be 
composed of the oxides of the metals and a peculiar acid, which they 
call fulminie acid, and that they are therefore salts. Fulminic acid con¬ 
sists of 26 parts or one proportional of cyanogen and 8 parts or one pro¬ 
portion of oxygen ; its equivalent is, therefore, 34. It is the true cyan- 
ous acid, and its salts are properly cyanites. Fulminating silver consists 
of one equivalent of oxide of silver 118 added to 1 equivalent of ful¬ 
minic or cyanous acid 34=152 its compound equivalent. There is a 
fulminate , or cyanate of mercury whose composition is similar, substitu¬ 
ting mercury for silver, (see § 422.) “ The great explosive powers of 

these compounds,” says Silliman, “ probably depend upon the mutual 
re-action of the elements producing aeriform bodies, which are suddenly 
evolved, and their evolution is not probably connected with electrical 
agency.”* 

* Silliman’s Ele. Vol. II. p. 339. Professor Silliman, who was seriously injured in 
making one of these preparations, suggests that great caution should be used with re¬ 
spect to them; and remarks that “ the little fire crackers or torpedoes are very improper¬ 
ly made subjects of amusement among boys. A twisted paper contains the fulminating 
silver mixed with sand to produce attrition, and to disguise the powder, and a lead shot 
to give it momentum, when it is thrown ; still, to a person unacquainted with the sub¬ 
ject, the paper presents nothing to the eye but a shot and some sand, with some 
minute white Jlocculi, which might well escape the eye of a common observer.” 

640. Oxide of silver. Silver tree. 

641. Fulminating silver. Detonating silver of Descotils. 



280 


INORGANIC CHEMISTRY. 


642. Chloride of Silver is produced when silver is heated in chlorine 
gas, and may also be prepared by mixing muriatic acid with a solution 
of nitrate of silver. It is at first white, but becomes black when exposed 
to the sun’s rays, disengaging muriatic acid and forming oxide of silver. 
This was formerly called muriate of silver ; but it is supposed that muri¬ 
atic acid in contact with the oxide of silver, becomes chlorine by impart¬ 
ing its hydrogen to the oxygen of the oxide to form water, and the chlo¬ 
rine unites with the metal. The chloride of silver is found native, when 
it is called luna cornea or horn silver. It is composed of one equivalent 
of silver and one of chlorine. A mixture of this chloride with chalk and 
pearlash moistened with water, is employed for silvering brass ; such as 
thermometer scales, clock dials, &c. 

643. Silver forms alloys with all the metals except nickel. 
Silver coin is composed of about l-10th part of copper, which 
renders it harder and firmer than pure silver. Silver vessels 
and ornaments are fashioned by hammering, as silver does not 
cast well. The surface is rendered more brilliant by boiling the 
articles in a copper vessel with a very weak sulphuric acid ; 
this takes up the copper of the alloy and the silver appears of a 
dead white Lastly it is burnished to heighten its lustre. Silver- 
plating is performed in various ways, and there is a great differ¬ 
ence in articles thus manufactured. Some are very beautiful, 
and wear for many years without change ; in others the plating 
or coats of silver sOon wear off at the edges and angles, discov¬ 
ering the copper beneath. 

644. Gold. Latin, Aurum; in French, or; called by the Al- 
chymists Sol , the sun, or king of metals. It has been known 
from the most remote periods* The Peruvians and Mexicans, 
when first visited by the. Spaniards were acquainted with gold 
and silver, though ignorant of iron and its uses. Its physical 
properties had been long known before its chemical relations had 
been thought of; the latter were developed in a degree, by the 
labors of the Alchymists; Gold is distinguished from all the other 
metals by its yellow color. It exceeds them all in ductility and 
malleability. It has been computed that 14,000,000 films of 
gold, like the coating of fine gold wire, would not exceed one 
inch in thickness, while the same number of sheets of common 
fine writing paper would form a thickness of about 3-4ths of a 
mile. The specific gravity of gold is a little over 19. It is the 
heaviest of the metals except platinum. It is more fusible than 
silver, being fused by the common blowpipe, when it is of a dark 
green color. It may be volatilized by the heat of a current of 


642. Chloride of silver. 

643. Alloys of silver. Silver coin, vessels, &c. Silver plating. 

644. Synonymes of gold. This metal early known. Peculiar prop¬ 
erties of gold. 



GOLD. 


281 


oxygen gas, directed upon burning charcoal; if a plate of silver 
be held over the vapor, it will become gilded. 

645. Gold is not oxidized by air or moisture. The only sol¬ 
vents of gold are aqua regia , (nitro-muriatic acid,) and liquid 
chlorine. According to Sir Humphrey Davy, chlorine is, in 
both cases the agent, since nitro-muriatic acid does not dissolve 
gold until it forms chlorine. That is, the hydrogen of the muri¬ 
atic acid leaves the chlorine and forms water with a portion of 
the oxygen of the nitric acid, reducing it to nitrous acid. The 
liberated chlorine, then, according to Davy’s theory, acts upon, 
and dissolves the gold, forming with it a chloride of gold. 

646. Oxides of Gold . It is yet considered uncertain whether 
there is more than one oxide of gold. The peroxide unites more 
readily with alkalies than with acids : and is, therefore, by some, 
considered an acid, called auric acid , and its salts, aurates . In 
this case, gold should be transferred to our 1st class of metals, 
or those which form acids with oxygen. But most Chemists 
consider this compound as a tritoxide , consisting of three atoms 
of oxygen, 24, to one of gold, 200, making its equivalent 224. 

It is obtained by boiling a solution of the chloride of gold with mag¬ 
nesia ; the oxide is precipitated along with a portion of magnesia ; nitric 
acid dissolves the magnesia without attacking the oxide of gold, which 
remains in the state of a yellow hydrate. It is rendered anhydrous by 
boiling, and then assumes the characteristic brown color of the peroxide. 
It is insoluble in water, combines readily with alkalies, but unites spar- 
ingly with acids. A powerful electric discharge through gold leaf or 
wire laid between papers gives rise to a purple substance which has been 
called the purple oxide of gold. It is stated that when the discharge is 
taken in a tube containing the gold, the air loses a portion of its oxygen. 
This purple oxide is considered by some a deutoxide , and by others to be 
merely gold in a state of minute sub-division. 

647. Chlorides of Gold. The same degree of uncertainty ex¬ 
ists with regard to the chlorides, as to the oxides of gold. Gold 
leaf introduced into chlorine gas trikes fire and burns ; and if it 
be suspended in water into which the gas is passed, it is dissolv¬ 
ed, and the solution may be concentrated by evaporation. This 
is probably the perchloride. By exposure to a moderate heat it 
parts with two thirds of its chlorine, and is converted into a yel¬ 
low insoluble proio-chloride. ’ ’* 

64S. The per-chloride is also called muriate of gold. The saturated 
solution of gold in nitro-muriatic acid yields crystals of a deep orange 

*Lib. Useful Knowledge. 


645. Effects of air and moisture upon gold. Aqua-regia. Action of 
nitro-muriatic acid upon gold. 

646. Oxides of gold. 

647. Chlorides of gold. 

648. Per-chloride of muriate of gold. 



2S2 


INORGANIC CHEMISTRY. 


color which rapidly attract moisture from the air. Heat expels the chlo¬ 
rine, and the gold remains as a spongy mass. The action of solar light 
is sufficient to reduce this chloride, and the glass which contains it, 
when it is thus exposed, will become lined with a brilliant coat of the 
revived gold. The chloride of gold is soluble, and when dissolved in 
distilled water, is in a fit condition for exhibiting the properties of dis¬ 
solved gold. This solution is often used in the arts for obtaining gijding 
by the agency of substances which, having a strong attraction for oxy¬ 
gen absorb it from the water of the solution, leaving the hydrogen to 
form hydro-chloric acid (muriatic) with the chlorine, and thus precipitat¬ 
ing the gold. Mrs. Fulliame gilded ribbons by moistening them with a 
solution of muriate of gold by means of a camels hair pencil, and hold¬ 
ing them over hydrogen gas as it was evolved 

649. Most of the metals effect the decomposition of this muriate, as 
also sulphurous and phosphorous acids, and many of the salts. The 
green sulphate of iron becomes red and precipitates metallic gold in the 
form of a dark cloud, which, when washed and melted, or rubbed, ex¬ 
hibits the proper color of gold. 

The proto-chloride of tin , precipitates the gold of a beautiful purple 
color forming what was formerly called gold pigment , precipitate of cas¬ 
sias , mineral purple and stannate of gold. It is this compound which 
gives to glass and porcelain a rich pink color. When potassa is added to 
the solution of perchloride or muriate of gold, a part of the gold uniting 
with the oxygen of the potash is precipitated in the state or an oxide, 
while the remaining portion of the gold and the whole of the chlorine 
combining with potassium forms a double chloride of gold and potassium. 
Similar double salts may be formed by the action of other alkalies, and 
by dissolving three hundred parts of gold in nitro-muriatic acid, and ad¬ 
ding 19 parts of common salt (chloride of sodium.) 

Liquid ammonia forms with the solution of gold a brownish precipi¬ 
tate called fulminating gold , which is analogous, 1st. in its detonating 
power. 2nd. to the compound of silver and ammonia. It is a compound 
of the oxide of gold with ammonia. On exploding, the oxygen of the 
oxide of gold combines with the hydrogen of the ammonia, forming wa¬ 
ter in the state of steam, while metallic gold and nitrogen gas occupy¬ 
ing 1000 times the volume of the fulminating powder, are liberated. 

If ether be poured into a solution of muriate of gold, it unites with 
the metal, and an etherial solution of gold floats on the surface of the 
hydro-chloric, or muriatic acid which was before combined with the 
gold. This was anciently called auriferous ether. It is sometimes used 
for gilding delicate steel instruments. 

650. Gold may be combined with Iodine, Bromine, Sulphur and Phos¬ 
phorus ; but the resulting compounds, have not been much studied, and 
are of no important use in the arts or in medicine. Sulphur does not 
act on gold as readily as upon silver ; the sulphuret of gold is formed by 
passing a current of sulphuretted hydrogen through a solution of chlo¬ 
ride or muriate of gold. 

651. Gold forms alloys with many of the metals. Antimony 


649. Decomposition of the muriate of gold. Precipitate of muriate of 
gold with the proto-chloride of tin. Precipitate with potassa, &c. Pre¬ 
cipitate of muriate of gold with liquid ammonia. Ether with muriate 
of gpld. 

650. Combinations of gold with Iodine, &c. Sulphuret of gold. 

651. Alloys of Gold. Carats of gold. 





CHLORIDE OF GOLD. 


283 


and zink destroys its ductility. Bismuth produces with it a brit¬ 
tle, pale, yellowish green alloy. Tin, or bismuth added to gold 
alloyed by copper, render it spongy and diminish its specific 
gravity. The fumes of lead give to gold externally pale yellow, 
and internally a brown color, and render it very brittle. When 
united with iron , gold becomes magnetic, and harder than steel. 
Copper is united to gold in coin, usually in the proportion of 
l-12th. Sometimes, as in Great Britian, the alloy is composed 
both of silver and copper. Nickel in a certain proportion, forms 
with gold an alloy resembling brass. Mercury readily unites 
with gold. A gold ring' becomes white by mere contact with 
mercury. This amalgam may be destroyed by exposing it to 
heat; the mercury volatilizes, and the gold remains unchanged. 
Silver gives to gold a paler color ; and, in a certain proportion, 
produces with it the green alloy of the goldsmith. All metals 
except silver and copper impair the ductility of gold. The fine¬ 
ness of gold is expressed by the number of parts of gold which 
it contains. It is supposed to consist of 24 parts called carats. 
Thus 24 parts carats fine, is pure, unalloyed gold. If it has 8 
parts of alloy, it is said to be 16 carats fine. The native gold of 
North Carolina is 23 carats fine. 

652. Gold is never found in combinations with earthy and silice¬ 
ous minerals ; but exists either in a pure metallic state, or alloyed 
with other metals. It is sometimes found crystalized in cubes or 
octahedrals united in little groups, but more commonly in thin 
scales, spangles or dust. It is found in primitive mountains, 
and in the sand in the beds of rivers, in alluvial formations, hav¬ 
ing been washed down from the mountainous regions. It occurs 
in veins of lead, and silver, and with iron pyrites. The most ex¬ 
tensive gold mines, are those of Mexico, Peru, Transylvania, 
and Hungary. It is found in the sands of Brazil, mingled with 
platinum and diamond. A rich and extensive region of gold 
exists in the United States ; it was discovered in North Caroli¬ 
na, but it has been traced north to Virginia, and. south to Alaba¬ 
ma and Georgia. 

653. Gold may be purified from mixture with the baser metals, by 
melting it with nitre, and by cupellation with lead ; also by dissolving 
in nitro-muriatic acid, filtering the solution, and adding proto-sulphate 
of iron, which precipitates all the gold in the metallic state, leaving the 
other metals in solution. It is freed from sand, and other foreign matter, 
when mixed with them, by repeated washings ; but if interspersed with 
much stony matter, it is calcined, pounded, washed, and amalgamated 
with mercury. The mercury is then volatilized by heat, and the gold 
remains fixed. Gold is separated from silver with greater difficulty than 

652. Gold as found in nature. Geological localities of gold. Geo¬ 
graphical localities. Gold mines in the United States. 

653. Modes of purifying gold. 



284 


INORGANIC CHEMISTRY. 


from any other metal; but when an alloy of gold and silver is dissolved 
in nitro-muriatic acid, the silver is found in the form of a white insoluble 
chloride, and the gold in solution. 

654. Platinum. This metal was first discovered by the Span¬ 
iards, near the river La Plata, in South America, the word plata 
signifying silver. Platinum was first carried to Europe in 1741, 
by Mr. Wood, an assay-master at Jamaica, though it had been 
previously described by Don Ulloa, who accompanied some 
French academicans to Peru in 1735. Platinum is the heaviest 
of all known substances. Its specific gravity is somewhat over 
20. It has a silvery whiteness, is very ductile and malleable, 
and so soft that it may be cut with scissors, or scratched with 
the nails. It is infusible by ordinary means, and does not even 
become oxidated with the most intense heat of the furnace. 
Thus crucibles which are to be exposed to intense heat are made 
of platinum. It is also a less perfect conductor of caloric than 
most of the metals, and on this account, and its infusibility, is 
used for spoons and tongs for holding substances when exposed 
to the action of the blow pipe. Thin leaves of platinum, are 
used for wrapping substances that are to be exposed to great 
heat. The scarcity of this metal, which renders it nearly as ex¬ 
pensive as gold,, prevents its being generally used, except for a 
few chemical, and scientific purposes. 

655. Like iron, platinum admits of being welded at a high 
temperature ; that is, at a white heat, an imperfect fusion takes 
place, which covers its surface with a kind of varnish, so that 
when different pieces are brought together in this state, they may 
be forged with a hammer, and thus be made to combine perma¬ 
nently. Platinum is easily fused by the oxy-hydrogen blow 
pipe. A piece of platinum wire melts when exposed in the fo¬ 
cus of that instrument, like wax in a common lamp ; it scintil¬ 
lates, drops in melted globules, and a portion rises in vapor. It 
is fused by powerful lenses, and by concave mirrors. It fuses 
also with fluxes, as borax, and glass, and if kept completely en¬ 
veloped in charcoal, it may be melted in that substance. 

656. Platinum is oxidated with great difficulty. Its only sol¬ 
vents are chlorine, and nitro-muriatic acid, and these solvents do 
not act upon it so rapidly as upon gold. It receives its highest 
portion of oxygen, by being heated with nitre. 

There are two oxides of platinum ; both of which yield their 
oxygen by heat, and leave the platinum in a pure metallic state. 

The protoxide is prepared by adding soda, or potassa, to a solution of 

654. Discovery of platinum. Origin of the name. Properties. Uses. 

655. Welding of this metal. Fusion of platinum by the compound 
blow pipe, &c. 

656. Oxides of platinum. Protoxide. Peroxide. 



SPONGY PLATINUM- 


285 


platinum in nitro-muriatic acid. The precipitate is found to consist of 
96, or one equivalent of metal, and 8, or one equivalent of oxygen. The 
equivalent, therefore, of the protoxide of platinum, is 96 Pla. added to 
8 ox.—104. This result is obtained by expelling the oxygen with heat, 
collecting and weighing it, ami then weighing the pure metal which re¬ 
mains. This proves also that 96 is the combining equivalent of pla¬ 
tinum. 

The peroxide is found on decomposition, to yield 16 parts, or 2 equiva¬ 
lents of oxygen, to 96 parts, or one equivalent of metal. The protoxide 
is black, the peroxide is of a brownish yellow color, when in the state of 
a hydrate ; but on becoming anhydrous by drying, it is black. The pe¬ 
roxide is obtained with difficulty ; for on attempting to precipitate it 
from the muriate by means of an alkali, it either falls as a sub-salt, or is 
held together in solution. Berzelius recommends that it should be ob¬ 
tained by decomposing the sulphate of platinum, with nitrate of baryta, 
and adding pure soda to the filtered solution, so as to precipitate about 
half of the oxide ; since otherwise a sub-salt would subside. Like pe¬ 
roxide of gold, it is a very feeble base, and is much disposed to unite 
with alkalies.— Turner. 

657. Muriate or Chloride of Platinum. Platinum does not 
take fire when introduced in thin leaves into chlorine gas, but a 
slow combustion of the two substances takes place, forming a 
chloride. When platinum dissolves in nitro-muriatic acid, a chlo¬ 
ride is formed. Some consider this compound while in solution, 
as a muriate , and that it becomes a chloride on drying. This is 
the per-chloride ; it is soluble in water, and decomposes with 
light. When heated, it gives up a portion of chloride, and be¬ 
comes th & proto-chloride. 

A double chloride of platinum and potassium is formed when the per- 
chloride of platinum is mixed with chloride of potassium. It is com¬ 
posed of 1 equivalent of bi-chloride of platinum, and one of chloride of 
potassium. When a solution of muriate of ammonia is added to the per- 
chloride of platinum, a light yellow precipitate is formed, commonly a 
double muriate of platinum and ammonia. 

When the ammonia-muriate is heated to redness, chlorine, and muri¬ 
ate of ammonia are evolved, and pure metallic platinum remains in a 
spongy mass, called spongy platinum, remarkable for its power of igni¬ 
ting a mixture of oxygen and hydrogen gases, and also the vapor of ether 
and alcohol. This peculiar property of platinum sponge was discovered 
in 1824, by Prof. Dobereiner, of Jena, and by him applied to the con¬ 
struction of lamps, for the production of instantaneous light, by means 
of a simple and ornamental apparatus. It is composed of two glass ves- 

657. Modes in which the muriate or chloride of platinum may be form¬ 
ed. Per-chloride. Proto-chloride. Double chloride of platinum and 
potassium. Double muriate of platinum and ammonia. Peculiar prop¬ 
erty of spongy platinum. Prof. Dobereiner’s invention. Theories to 
account for °the action of hydrogen on platinum sponge. Fulminating 
platinum. Combinations of platinum with phosphorous, &c. 

25 




286 


INORGANIC CHEMISTRY. 


sels a and b. The vessel a, is en¬ 
compassed by a coil of zink in the 
tubular extremity which extends 
nearly to the bottom of the lower 
vessel, b. Sulphuric acid being 
poured into the lower part of the 
apparatus, the smaller vessel is then 
inserted, its tube being so fitted to 
the neck of the other vessel, by 
grinding, as to be air tight. Hy¬ 
drogen gas is now evolved by the 
action of the zink upon the water 
of the sulphuric acid, and by its 
pressure, forces part of the liquid 
into the upper vessel through its 
tube. On opening the stop cock, 
c, the gas issues forth in a jet, 
which inflames the spongy plati¬ 
num contained in a brass cup at p ; 
the platinum ignites the stream of hydrogen, and the latter lights the ta¬ 
per which is situated between p and c, or in the current of burning hy¬ 
drogen. A candle or taper applied to the jet, may be lighted at any mo¬ 
ment, by turning the stop cock to allow the hydrogen gas to escape. 

It has been suggested that the minutely divided spongy platinum, by 
absorbing a large portion of hydrogen in its pores, generates heat, which 
the oxygen of the air kindles into flame. Another theory supposes that 
*the sudden ignition of the hydrogen, arises from a galvanic action taking 
place between that and the platinum; the hydrogen acting the part of 
the zink plate. 

Fulminating platinum is formqd by decomposing sulphate of platinum 
by excess of ammonia^ One grain heated to 400° Fahrenheit, explodes 
with a flash, ana a report louder than that of a pistol. 

Platinum unites with phosphorus and sulphur in two proportions; and 
is capable of combining with most of the metals. 

658. The ore of platinum is found in nature, combined with 
the four recently discovered minerals, viz : iridium , rhodium , pal¬ 
ladium , and osmium , and also iron and chromium. It is usually 
seen in flat grains, seldom in pieces so large as an ounce weight. 
It has been found most abundantly in South America; but a 
piece of 9 1-2 pounds weight has been found in Siberia, where 
it exists in auriferous (or gold bearing sands) near the Uralian 
mountains. The four recently known metals found in connec¬ 
tion with platinum, are yet little known ; and have been procur¬ 
ed, but in small quantities. When platinum ore is digested in 
nitro-muriatic acid, the platinum, together with the palladium, 
rhodium, iron, copper, and lead, is dissolved; while a black 
powder, consisting of osmium, and iridium, remains. These va¬ 
rious metals are separated and purified by very difficult and com¬ 
plicated processes. 



658. Ore of platinum, with what metals combined, &c. 












PALLADIUM. 


287 


659. Palladium , is of a silver color, very malleable and duc¬ 
tile. Neither atmospheric air, nor oxygen, has any action upon 
it. \ auquelin observed that under the gas blow pipe it burnt 
with an appearance of brilliant coronas , or aigrettes of flame. 
When a jet of hydrogen is passed upon spongy palladium, the 
metal reddens, and water is formed, by the combination of the 
hydrogen with the oxygen of the air. Palladium is acted upon 
by several of the acids, but most powerfully by the nitro-muri- 
atic. 


Oxide of palladium is formed by adding potash to a solution 
of the chloride of palladium ; the precipitated hydrate, is orange 
colored, but becomes black on dyeing. It forms beautiful red col¬ 
ored salts. This oxide is supposed to be a compound of 1 equiv¬ 
alent of pal. 56 added to 1 ox. 8—64. 

Berzelius has discovered two chlorides of palladium. This 
metal also has been combined with sulphur, selenium, and sev¬ 
eral other metals. Palladium was first introduced into England 
by Dr. Wollaston, in 1803; and named after the planet Pallas, 
then recently discovered. 

660. Rhodium. Dr. Wollaston obtained this metal from plati¬ 
num ore, during the period he was making his observations upon 
palladium. Vauquelin and Berzelius have since examined it. It 
is named from the Greek rodon , a rose, on account of the rose 
color of its muriate or chloride. 

It does not dissolve in any acid when pure ; but when combined with 
other metals, as copper, or lead, it may be dissolved by nitro-muriatic 
acid. It is found in the solution of the ore of platinum ; and is separa¬ 
ted from the various substances with which it is here associated, by pe¬ 
culiar processes, which require much care and skill. After various 
washings and precipitations, in order to disengage it from foreign sub¬ 
stances, it remains alloyed only with platinum. This alloy is dissolved 
by nitro-muriatic acid, the solution mixed with muriate of soda, and then 
evaporated. The dry mass which remains, consists of two double chlo¬ 
rides, viz: that of platinum, and sodium, and of rhodium and sodium 
On adding alcohol to this compound, the chloride of platinum and sodi 
um dissolves, and may thus be separated. The chloride of sodium and 
rhodium may be dissolved in hot water, and a rod of zink inserted in the 
solution, precipitates rhodium in the form of a black powder. This ef¬ 
fect is owing to the attraction of the chloride of sodium for lime, which 
by uniting with it, liberates the rhodium that was held in combination, 
as lead is disengaged by the decomposition of the acetate of lead, in the 
formation of the lead tree, (623.) 

661. The black powder in which rhodium is at first procured, 
requires for its fusion, the strongest heat of the wind furnace. 


659. Properties of palladium. Spongy palladium. Oxide. Chlorides 
&c. Introduction into England. Name. 

660. Rhodium, when first obtained. Name. How dissolved. How 
obtained from its solution with platinum. 

661. Properties of rhodium. Oxides of rhodium. Salts. Chlorides. 



288 


INORGANIC CHEMISTRY, 


In its pure metallic state, it has a whitish color, and is very brit¬ 
tle and hard ; its specific gravity is about 11. It is not easily 
attracted by oxygen; but oxidates when heated with nitre. 

Thomson states that there are two oxides of rhodium; the black pro¬ 
toxide, containing 44 parts rhodium, and 8 oxygen, and the yellow perox¬ 
ide , containing 44 rhodium, and 16, or two equivalents of oxygen ; this 
hypothesis would give 44 for the equivalent atom of rhodium. The pe¬ 
roxide is the basis of the salts of 'rhodium, all of which are either red or 
yellow. According to Berzelius, there are two chlorides of rhodium, the 
one yellow, and the other red ; they are formed by passing chlorine gas 
over the metal. 

662. Iridium. The name of this metal, is from iris, the fain- 
bow, on account of the changeable hue of its salts. It was dis¬ 
covered by M. Descotils, in 1803. On digesting platinum ore 
with nitro-muriatic acid, a portion, in the form of a black pow¬ 
der, remains undissolved ; this consists of a mixture of iridium, 
and another metal called osmium. Iridium is very infusible. It 
was melted by Mr. Children’s powerful galvanic battery, and 
appeared as a brilliant, porous, metallic mass, whose specific 
gravity was 18.06. It is remarkable for its hardness, and for 
its power of resisting the action of acids ; on account of which 
properties, it is used for the points of metallic pens, as other 
metals soon become corioded by the gallic acid contained in ink, 
and the pens are thus rendered unfit for use. The peculiar hard¬ 
ness of platinum is supposed to be caused by the presence of 
iridium. According to Berzelius, solutions of iridium may, 
without the aid of any foreign substance, be obtained of all the 
hues of the rainbow. 

663. Osmium. The name from the Greek osine , odor, was giv¬ 
en on account of the strong odor of its oxide, resembling that of 
chlorine. 

Combined with iridium, it remains undissolved when platinum ore is 
digested in nitro-muriatic acid, and, as has been remarked, (§ 622) the 
two appear together in the form of a black powder. These metals may 
be separated by distilling the powder in a retort with nitre; the osmium 
will sublime in the form of an oxide, leaving the iridium with the nitre 
from which it may be separated by dissolving the salt, (nitrate of pot¬ 
ash,) in boiling water; iridium remains in the form of a black powder. 
Berzelius, by passing the oxide of osmium, mixed with hydrogen gas, 
through a heated glass tube, obtained a compact precipitate of osmium’ 
having a metallic lustre. When heated in the open air, it oxidizes and’ 
dissipates in vapor. Its oxide is soluble in water, and emits a peculiar 
pungent odor. Berzelius states that there are at least, three oxides of 


662. Derivation of the name iridium. Discovery. Found in plati¬ 
num ore. How fused? Properties, &c. * 

663. Origin of the name osmium. Manner in which osmium and 
iridium are separated. Osmium obtained in a metallic state. Its oxi¬ 
dation. Oxides of osmium. Chlorides, and other compounds of osmi- 
um. Tests of osmium. 




CLASSIFICATION OF METALS, 


289 


osmium, containing 1, 2, and 4 equivalents of oxygen. He considers 
eoxide which emits the peculiar odor, as the deutoxide. 

Osmium heated with chlorine, forms a chloride , of a beautiful 
blue color; if heated with an excess of chlorine, a red per- 
chloride sublimes. Osmium unites with sulphur, and forms 
ductile alloys with gold and silver. This metal in solution, 
when tested with nut-galls, becomes first purple, and then blue; 
with ammonia, it changes to a yellow color. 


664. CLASSIFICATION OF METALS. 


CLASS I. 

Metals which form acids with oxygen. 


1. Arsenic. 

Equiv. 

38 

2. Antimony. 

44 

3. Columbium. 

144 

4. Titanium. 


5. Chromium. 

32 

6. Molybdenum. 

48 

7. Tellurium. 

32 

8. Tungsten. 

96 

9. Vanadium. 


10. Uranium. 

208 

11. Manganese. 

28 

12. Cobalt. 

26 

13. Tin. 

58 


CLASS III. 

Metals whose oxides are earths. 


Equiv. 
10 


1. Aluminum. 

2. Zirconium. 

3. Glucinum. 

4. Yttrium. 

5. Thorium. 

CLASS IV. 

Metals whose oxides are neither acids, 
alkalies, nor earths. 


CLASS II. 

Metals whose oxides are fixed alkalies, or 
alkaline earths. 

order i. Metals whose oxides are fixed 
alkalies. 

Equiv. 

1. Potassium. 40 

2. Sodium. 24 

3. Lithium. 10 

order n. Metals whose oxides are alkaline 

earths. 

4. Barium. 70 

5. Strontium. 44 

6. Calcium. 

7. Magnesium. 


1. Iron. 

2. Nickel. 

3. Zink. 

4. Cadmium. 

5. Cerium. 

6. Lead. 

7. Copper. 

8. Bismuth. 

9. Mercury. 

10. Silver. 

11. Gold. 

12. Platinum. 

13. Palladium. 

14. Rhodium. 
20 15. Iridium. 

12 16. Osmium. 


Equiv. 

28 

26 

36 

56 

50 

104 

64 

72 

200 

110 

200 

96 

56 

44 


665. We have now completed a brief examination of the me¬ 
tals. In an elementary course of instruction in chemistry, little 
more can be expected, than that the pupil will gain a knowledge 
of general principles, and become familiar with a sufficient num¬ 
ber of applications to illustrate these principles to his understand- 


664. What metals of the 1st class ? 
2d Order. 3d Class. 4th Class. 

665. Remarks. 

25 * 


2d Class, 1st Order. 2d Class, 




290 


INORGANIC CHEMISTRY. 


ing, and to impress them upon his memory. He is thus furnish¬ 
ed with a key which will enable him, thereafter, to enter into 
nature’s laboratory and examine for himself the wonderful 
operations which are there going on. He has learned to avail 
himself of the aids which the labors of others afford him ; and 
may consider, that he now stands at that point where the great¬ 
est Chemists, who have preceeded him, once stood. There was 
a time when they were beginning to learn ; when the simplest 
instance of chemical composition or decomposition caused their 
bosoms to dilate with emotions of delight and induced them to 
exclaim, u If science can do this, what can it not perform.” A 
glorious future of discovery and invention dawned upon their 
minds, and they followed with untiring steps through labors and 
difficulties, until success and honor crowned their efforts. Let 
not the American Student wrapping himself in the mantle of 
indolence, imagine that Lavoisier and Davy, Vauquelin and 
Berzelius have discovered all that is to be learned in this depart¬ 
ment of human knowledge. He should rather consider, that 
their discoveries and inventions have put into his hands im¬ 
portant instruments for the development of new facts, and the 
discovery of new principles. 

The God of Nature, who has placed no limits to man’s de¬ 
sire of knowledge, renders also, the field of inquiry equally il¬ 
limitable. One newly discovered region in science opens a 
pathway to many others, and thus there is, and ever must be, an 
infinite progression in knowledge, suited to the capacities of the 
immortal mind, and corresponding with the character and digni¬ 
ty of an infinite Creator. 


SALTS. 

LECTURE XXVIII. 

CRVSTALIZATION. CLASSIFICATION OF SALTS. SALTS OF THE 
OXACIDS. 

CRYSTALIZATION. 

666. Crystals are formed of similar particles of matter, which 
according to some wonderful and unknown law of nature arrange 
themselves into regular geometrical forms. There is nothing in 


666 Formation of crystals. 





CRYSTALIZATION. 


291 


organic nature more admirable than that process of crystaliza¬ 
tion, where each particle or molecule takes its proper place in 
order to form, by aggregation, that kind of figure which is pe¬ 
culiar to its own species of matter. The law of molecular attrac¬ 
tion may account for the aggregation of particles, but it does not 
explain why they always under certain circumstances arrange 
themselves in perfect symmetry ; nor can any satisfactory rea¬ 
son be given for this phenomenon. 

667. Solid bodies appear under a variety of forms. In the 
vegetable and animal kingdoms, figure is the result of organiza¬ 
tion. The plant bursting from the seed, puts forth roots, stem, 
leaves, and flowers ; and the animal, exhibits its head, limbs, 
and peculiar features. In both, organic laws prevail, and a liv¬ 
ing principle converts inorganic matter into nourishment, 
assimilating it to the substance with which it incorporates In 
the mineral kingdom, solids are either irregular, amorphous* 
masses, in which the particles cohere without regular order, or 
exhibit a crystalline structure. 

668. If we dissolve crystals of alum (a double salt of alumine and pot¬ 
ash) and suffer the solution to evaporate slowly, we shall again have the 
same octahedral, or eight sided crystals as those we dissolved. But if the 
liquid be expelled by a sudden and strong heat, we shall find the salt in 
a shapeless mass, or in confused and irregular crystals. 

If we plunge a lump of alum into a tumbler of cold water, we shall, 
after a few days, find the surface of the salt eaten, and carved out into a 
variety of regular forms. (See fig. 93.) 

Let a few drops of the solution of alum in water be put upon a glass 
plate and suffered to remain undisturbed a few days, the particles of alum 
when examined with a microscope, will be found to have arranged them¬ 
selves in small octakedra or eight sided figures, (see fig. 94.) Crystals 
are liable to certain modifications ; thus in eight sided or octahedral 
figures we may find some whose angles are truncated, or appear as ifthey 
were cut off or replaced by secondary surfaces ; sometimes the edges are 
also similarly modified ; at A, (fig. 95,) angles only of the octahedron are 
truncated, at B, the edges only, at C, both the angles and edges. 

669. As the soluble salts when thus evaporated, usually assume dis¬ 
tinct figures, crystalization gives to the chemist and mineralogist a val¬ 
uable method of determining the composition and nature of different 
bodies. The smallest crystals obtained from a drop of solution are 
equally perfect in figure as the largest ones, formed in greater quantities 
of the fluid; and when viewed through a microscope furnish evidence, 
equally satisfactory, of the nature, of the crystalized salt. 

* From the Greek a , destitute of and morphe , regular shape. 


667. Forms of organic bodies. Forms of minerals. 

668. Effects of slow and sudden evaporation. Alum crystals. Crys¬ 
tals with truncated angles and edges. 

669. Advantages afforded by crystalization to the Chemist and Miner¬ 
alogist. Small crystals equally perfect in form as larger ones. Compari¬ 
son of the crystals of different salts. 



292 


INORGANIC CHEMISTRY. 


Fig. 93. Fig. 94. 



670. Different salts may be thus conveniently evaporated in separate 
small glasses, and their different crystals compared. Take common salt, 
Glauber’s salt, Epsom salt and nitre or salt petre, of each a teaspoonful, 
and put them Separately into wine glasses ; fill the glasses with water, 
and occasionally stir the mixtures to facilitate their solution ; when the 
salts are entirely dissolved, put a drop of each solution upon a clean plate 
of glass, placed in the sun. As the liquid evaporates, crystals peculiar 
to each kind of salt, may be seen with a microscope ; a common salt will 
appear in cubes; Glauber’s salt in irregular six sided prisms; Epsom 
salts in four sided prisms ; nitre in six sided prisms ; (see fig. 96.) Glau¬ 
ber’s salt and nitre, though resembling each other in the form of their 
crystals, exhibit a marked difference when exposed to the air ; crystals of 
the former effloresce, that is they lose their transparency, and crumble to 
powder, while those of the latter are not changed by the atmosphere. 
Nitre is an anhydrous salt, or a salt that contains no water of crystal- 
ization. 


Fig. 96. 



Crystals of common salt. Crystals of Epsom salts. 


670. Crystals of common salt, Glauber’s salt, Epsom salt and nitre. ' 




























CRYSTALIZATION. 


293 



Crystals of Glauber Salts. Crystals of Nitre. 


671. Crystals, in respect to forms, are divided into primitive or 
fundamental forms, and secondary or derived forms. It is found 
that though the same substance, may assume different crystaline 
forms, these are, in general, allied to each other. 

1 Jr-*' 

Fig. 97. 672. The most common primitive 

forms are the four sided prism , cube, 
rhomboid, tetrahedron, octahedron , 
rhomboidal, dodecahedron, Dodeca- 
dron with triangular faces, and the 
triangular prism. 

The Four sided prism, has its sides 
composed of four equal oblong parrn- 
llelograms, and its ends of two square 
parallelograms ; it is sometimes called 
a square prism. The cube has six 
square equal'sides. 

The rhomboid has its op¬ 
posite sides equal and paral¬ 
lel, but none of these are 
square, each having two ac¬ 
ute and two obtuse angles, 
while each side of the cube 
has four right angles. 

The tetrahedron is inclu¬ 
ded within four, equilateral 
triangular planes. 

The octahedron , or eight sided figure has all its planes equal, and sim¬ 
ilar triangles. It may be considered a compound of the tetrahedron. The 
cut represents at a, a crystal shaded, and at b, the same in outline. 

The hexangular, of six sided prism ; in this, the six sides are similar 
parallelograms, not square, but oblong ; it has six edges and six angles; 
that is, it is hexaedral and hexagonal. 

The rhombic dodecahedron: has twelve sides; each plane being a 
rhomboid having two acute, and two obtuse angles. 

The dodecahedron with triangular faces has twelve, equal, triangular 
sides. 


671. Division of crystals into primitive and secondary forms. 

672. Most common primitive forms. Four sided prism. Cube. Rhom¬ 
boid. Tetrahedron. Octahedron. Hexangular prism. Rhombic dode- 
padron. Dodecahedron with triangular faces. Triangular prism. 


















294 


INORGANIC CHEMISTRY. 


a b Fig. 99. 



Rhombic. Dodecahedron. Dodecahedron with triangular faces. 


Fig. 100. 




Triangular Prism. Parallelopiped. 


673. The primitive forms of crystals may 
be further reduced to three ; the triangular 
or most simple prism, the tetrahedron or 
most simple solid, and the parallelopiped. 

674. To some one of these varie¬ 
ties of forms, all crystals, by mechani¬ 
cal division may be reduced. Dis¬ 
coveries in crystalography, as in other 
departments of science, have been, in 
part, the result of accident. Gahn, 
a Swedish professor of mineralogy accidentally broke a piece of 
dog tooth-spar,* and found it was an aggregate of rhomboidal 
crystals. The Abbe Hauy, a celebrated French philosopher, 
when examining an expensive collection of minerals, let fall a 
beautiful crystal, which separated into many pieces. Struck with 
the smooth and brilliant surfaces of these fragments, the Abbe 
was led to an examination of the structure of crystals. He found 
that all crystals are easily divided in certain directions, leaving 
smooth and regular surfaces ; that the smaller crystals thus ob¬ 
tained, may again be divided into other minute crystals ; but the 
same form is observed in all. Thus calcareous-spar, crystalizes 
in rhomboids, fluor-spar in cubes, and quartz in six-sided 
pyramids. 

* Crystalline carbonate of lime. 


673. Triangular prism. Parallelopiped. 

674. Circumstances which have led to discoveries in crystallography. 
The Abbe Hauy led to examine the structure of crystals. Planes, edges 
and angles. 






































CRYSTALIZATION. 


295 


The surface of crystals are called planes or faces. The lines 
made by the meeting of two planes are called edges ; the meeting 
of three planes forms what is called a solid angle. 

Fig. 101. Fig- 101, shows a cube in which «, a , «, are planes, b, b , 
are edges and c, c, solid angles. Thus the cube has 
six planes or faces, twelve edges, and eight solid 
angles. 

675. The primary cubic form may be modified by 
various circumstances. Thus, if instead of the solid 
angles of a cube, the faces be triangular, we should 
have a different form of crystal. The three primary 
forms (see § 673,) were by Hiluy considered as be¬ 
longing to the integrant molecules of all crystalline 
b c bodies, both primary and derivative. u But it is not 

difficult, as Dr. Wollaston suggests, to conceive that these primitive 
forms may themselves be procured by certain arrangements of spherical 
or globular particles ; thus, four balls, arranged as at a, (fig. 102,) give 
the element of the tetrahedral form ; and six balls, arranged as at 
Z>, that of the octahedron, and so of the others. Fig. 103, represents a 
number of spherical particles aggregated to form the tetrahedron and 
triangular prism. Fig. 104, represents an aggregation of similar parti¬ 
cles, to form the rhomboid and cube. Fig. 105, represents the octahe¬ 
dron and four sided prism formed in a similar manner. Instead, there¬ 
fore, of assuming several distinct geometrical solids as primitive forms, 
some philosophers refer to the sphere, or spheroid, as the source of all, 
and assume it as the figure of the ultimate, mechanical particles of 
matter.” 




Fig. 104. 


676. The secondary forms of 
crystals are supposed to grow 
out of the integrant molecules 
and primitive forms, as follows. 
The molecules first unite to 
produce the primitive form, and 
from this proceeds the secon¬ 
dary form by the application of 
successive layers of the inte¬ 
grant molecules, parallel to its 
planes and faces. Thus, “ if a cube be increased by layers of particles 
applied to all its sides, the edges of the layers being parallel to those of 
th Q cube and each layer being made less than that immediately preceding 



675 Modifications of the primary form. Hauy’s opinion respecting 
the primary forms. Dr. Wollaston’s suggestion. Opinion of some with 
respect to the figure of ultimate atoms. 

676. Manner in which the secondary forms proceed from the primary 














296 


INORGANIC CHEMISTRY. 


it, by one row of particles on each of its edges, a dodecahedron, or twelve 
sided solid, with rhombic faces will be produced.”* 

Fig. 105. Fig. 106. 



Rhombic Dodecahedron. 


677. Crystals not only differ one from another in form, but those of 
similar form differ in the angles made by the inclinatian of the faces. 
Thus in the rhomboid, which is characterized by having one of its adja¬ 
cent angles smaller than a right angle and the other larger, it is evident 
that,the one angle may consist of almost any number of degrees less than 
90, and the other of any number below 180, though this must be the 
amount of the two angles taken collectively; because the four angles of 
the crystal, must, together be equal to four right angles, thus 90X4=360, 
which is the nurtiber of degrees of a circle, by which angles are measured. 
Thus the primitive form of calcareous spar is a rhomboid whose faces are 
inclined at angles of 105°, o' which is more than a right angle and 74°, 
5' which is less than a r^ght angle, these numbers added together make 
180® which is the sum of two right angles. The primitive form of the 
mineral called tourmaline, is an obtuse rhomboid, the largest angle of 
which is 113° 10'. 

N * * \ v C . . * % . * - • . * - 

WbXXV , ’ ** «*■•*-. •• . ^ n." 

* Dr. Hare. 


677. Crystals of similar form may differ in the size of their angles. 























CRYSTALIZATION. 


297 


Fig. 107. 



678. An instrument called 
a goniometer * has been in¬ 
vented for measuring the 
angles of crystals. Its ope¬ 
ration is founded upon the 
mathematical proposition t 
that “ the opposite angles 
made by any two lines in 
crossing each other are 
equal.” Thus the angle 
made by the arms B B,B C B, 
of this instrument, above and 
below the pivot on which 
they revolve, are equal to 
each other. Therefore if 
the angle of a crystal be 
placed at C, and the arms of 
the goniometer made to close 
Goniometer, or instrument for measuring the angles upon its planes, a similar an- 
of crystals. gle will be made by the arms 

on the opposite side,and this angle may be known by examiningthe semi¬ 
circle, A A, which is graduated into 180°. An instrument called the 
reflective goniometer has been invented by Dr. Wollaston, which measures 
with great accuracy the angles of the most minute crystals ; here instead 
of the crystal itself being employed as a radius, rays of light reflected 
from the brilliant angles are made subservient to this purpose. 

679. In order to obtain large and well formed crystals, three things are 
necessar y, time, space and repose. Time is required for the evaporation 
of the superabundant fluid and the arrangement of the molecules of the 
salt according to the laws by which they act, when permitted to move 
freely. It is a general rule the longer crystals are in forming, the more 
perfect is their form, the greater their size, and the harder and more 
transparent their texture. An evaporation too rapid precipitates the 
molecules, upon each other, and obliges faces to unite, which otherwise 
would not have been brought into contact. In this case the crystal is 
neither transparent nor regular. Space is also necessary; when the li¬ 
quid is very rapidly evaporated, the salt which was held in solution forms 
a concrete mass, with scarcely a trace of crystalization. Nature does 
not like to be cramped in her operations ; it is necessary, therefore, that 
the molecules may move about freely ; for this reason broad and shallow 
vessels are usually preferred in order to carry on the evaporating pro¬ 
cess ; these should be covered with gauze or some other substance, which 
will keep out the dust without preventing the access of the air. Regular 
crystals cannot be obtained without repose. When there is external 
action the molecules do not act freely among themselves. Agitation 
produces irregular crystals. 

* From the Greek gon an angle, and metron measure. 

t Euclid, B. I. prop. 15. 


678. Goniometer. Reflective goniometer. 

679. What is necessary in order to obtain large and perfect crystals ? 

26 














298 


INORGANIC CHEMISTRY - . 


Fig. 108. 


680. We have considered the 
subject of crystalization chiefly in 
respect to salts ; but metals often 
assume very beautiful, and regular 
crystaline forms. This may take 
place either by liquefying them by 
fusion, or by converting them into 
vapor ; and as the liquid becomes 
solid by cooling or the vapor by 
condensing, the particles arrange 
themselves in crystals of greater or 
less regularity. Tin, lead, antimo¬ 
ny, and bismuth, all afford crystals. 
For this purpose they may be melt¬ 
ed in a crucible : when the surface 
cools it should be pierced, and the 
liquid metal within poured out: 
when the hollow mass has become 
quite hard, it may be broken and 
the interior of the cavity will be found lined with crystals. Fig. 108, 
represents the crystalization of bismuth effected in this manner. 

681. Crystals are to the mineralogist, what flowers are to the 
botanist. He reads the chemical constitution of minerals in the 
mechanical figure which they present, as the botanist decides by 
the organs of the plant, the class or group to which it belongs. 
But as various accidental circumstances to which flowers are not 
exposed, affect the forms of crystals, it is often necessary that the 
inquirer should examine the constituent parts ; and this can only 
he done by the aid of chemical analysis. 



Salts. 


682. To facilitate the study of the Salts, they have been very 
properly arranged in groups, or genera. As every acid, with 
few exceptions, unites with every alkaline base, the different kinds 
of salts thus formed are very numerous, amounting to more than 
2.000, though not more than thirty were known a hundred years 
ago. The names given to the salts were often merely arbitrary ; 
but in the present nomenclature, the name of a salt expresses its 
composition , and the knowledge of its composition recals its name. 
The name of the genus is derived from the acids , that of the 
species, from the base ; thus sulphate is a generic term including 
various species, as sulphate of soda, sulphate of lime, sulphate of 
potassa, &c. 


680. Crystalization of metals. 

681. Value of crystals to the mineralogist. 

682. Importance of some mode of classifying salts. Difference between 
the old names of the salts and those which are founded on the chemical 
nomenclature. 


















CLASSIFICATION OF SALTS. 


299 


683. The acids are divided into two classes ; 1st Oxacids , or 
acids in which oxygen is united to a combustible body ; and 2nd 
Hydracidsj or acids composed of hydrogen and some other body. 
Until the great revolution in chemical science, which took place 
about the year 1775, it was supposed that oxygen was the only 
acidifying principle. Berthollet was the first to suggest doubts 
on this subject, by affirming that sulphuretted hydrogen ought to 
be regarded as an acid, though composed of hydrogen and sul¬ 
phur. The discovery of iodine and chlorine, furnished new and 
convincing proofs that the acidifying property is not confined to 
oxygen, but exists in other bodies. The number of the binary 
oxacids amounts to more than twenty, while that of the hydrac- 
ids is much less. 

684. Classification of salts. 

Order /, Salts of the oxacids. 

Order //, Salts of the hydracids. 

Every acid is capable of forming a salt with a base ; and such salt 
may be considered as a distinct genus ; but as one element often forms 
with oxygen several acids, which though they possess individuality, are 
very similar, we shall consider the various salts formed by such acids as 
constituting divisions of a genus ; thus the nitrates and hypo-nitrates will 
be classed as sub-genera , under the genus nitrate. 

ORDER I. SALTS OF THE OXACIDS. 

GENUS I.-SULPHATES. 

685. Of all the acids, none has a more decided tendency to com¬ 
bine with salifiable bases, than the sulphuric. The number of sul¬ 
phates is of course very great. Many of these salts are found in 
nature, and many are used in the arts. 

They have mostly a brittle taste ; and are decomposed by baryta, which 
has a stronger affinity for sulphuric acid, than any other base. All the sul¬ 
phates may be decomposed by carbon at a high temperature. The acid 
and oxide are both decomposed, the oxygen forming with the carbon, car¬ 
bonic acid, and the sulphur forming with the metal, a sulphuret. At 
common temperatures, the sulphates neither effervesce with acids nor 
give off vapors; but the sulphuric acid, by a high heat, maybe displaced 
by boracic, phosphoric, and arsenic acids. Those which contain no 
water of crystalization, as the sulphate of iron, when exposed to great 
heat, yield a portion of anhydrous, sulphuric acid. Six of the sulphates 
are insoluble in water, viz.: the sulphate of baryta, tin, antimony, bis- 


683. Two classes of acids. 

684. Two orders of salts. What constitutes a general character in 
respect to salts? . Sub-genera of salts. 

685. Why is number of sulphates great ? General properties of this 
genus of salts. Decomposition, <fcc. Insoluble sulphates. Soluble sul¬ 
phates with muriate of baryta. Native sulphates, &c. 



300 


INORGANIC CHEMISTRY. 


muth, lead, and mercury ; the sulphates of lime, strontia, silver, and a 
few others are sparingly soluble ; all the others are soluble in water. The 
soluble sulphates form with muriate of baryta, a dense white precipi¬ 
tate, which is the sulphate of barytes, and is insoluble. 

There are many native sulphates ; those of lime and baryta are 
most abundant. Those which are employed in the arts, are usu¬ 
ally extracted from native minerals. Some are prepared directly 
by art, and many by double decomposition. 

686. Sulphate of potassa, is a white salt, of an acrid and bitter 
taste. 

This salt was formerly much valued in medicine. It is known 
in commerce, as vitriolated tartar , and sometimes used in prefer¬ 
ence to Glauber’s salts. It is of use in the manufacture of alum, 
glass, and salt petre. It is not found native among mineral sub¬ 
stances, but exists in the ashes of tobacco and some other vege¬ 
tables. The bi-sulphate contains twice as much acid as the sul¬ 
phate. 

687. Sulphate of soda was discovered by Glauber, a German 
Chemist in the process for obtaining muriatic acid, by decompo¬ 
sing common salt with sulphuric acid. A precipitate of soda 
was obtained which has been named Glauber’s salt in honor of 
its discoverer. It is contained in the waters of some mineral 
springs, in sea water, in the ashes of sea weed, and sometimes 
effloresces at the surface of the earth, and upon the walls of cel¬ 
lars, and other excavations. It exists in a mineral found in 
Spain, called Glauberite. 

It is a colorless, and very bitter salt, capable of forming very large 
crystals, and containing 58-100th of the water of crystalization. Accor¬ 
ding to Berzelius, the crystals are composed of 72 parts, or one equiva¬ 
lent of sulphate of soda, and 90 parts, or ten equivalents of water. 
They undergo the watery fusion on exposure to heat. This salt readily 
effloresces in the air; and thus, by losing its water of crystalization or 
more than one half its weight, it becomes more than twice as strong. 

This is One of the essential medicines of the the family dis¬ 
pensatory. It is used in the arts for the preparation of carbon¬ 
ate of soda and manufacture of glass. Bi-sulphate of soda is form¬ 
ed by adding sulphuric acid to a solution of sulphate of soda. 

688. Sulphate of ammonia. This salt exists in small quanti¬ 
ties in nature ; in the neighborhood of volcanoes, and in the wa¬ 
ters of the Tuscan lakes. It is usually prepared by the direct 
combination of ammonia with sulphuric acid. 

Sulphate of ammonia may be obtained by distilling the soot of pit 

686. Properties of sulphate of potassa. Uses. Where found. 

687. Discovery of sulphate of soda. Common name. Where it ex¬ 
ists in nature. Properties. Crystals. Degree of temperature at which 
water most readily dissolves it. Effect of the effervescence of this salt. 
Uses. Bi-sulphate of soda. 

688. Sulphate of ammonia. 




SULPHATE OF LIME. 


301 


coal. According to Silliman,* the ammonia does not exist in the coal, 
but is formed by the union of the nitrogen of the air, with the hydrogen 
of the coal; while the oxygen of the air and the sulphur of the coal 
form sulphuric acid; and the union of the latter with ammonia, produ¬ 
ces the sulphate. 

689. Sulphate of Baryta , called heavy spar is an abundant pro¬ 
duct of nature. It usually exists in veins with metals. It is 
often found with antimony and manganese. It is sometimes 
found in fibrous masses, or an earthy state, but often crystalizefl. 
It is wholly insoluble in water, and bears the most intense heat 
without fusion, or decomposition. 

The affinity of pure baryta for sulphuric acid, is so great, that when 
they are brought in contact, ignition is produced. This affinity enables 
baryta to separate sulphuric acid from all its combinations, giving a sen¬ 
sible white precipitate, in a solution containing no more than one mil¬ 
lionth part of baryta. All the salts of baryta, except the sulphate, are 
poisonous; and this exception is owing to the perfect insolubility of the 
salt, in the juices of the stomach. If, therefore, any of the poisonous 
salts of baryta be swallowed, diluted sulphuric acid, a solution of sul 
phate of soda, or any other alkaline sulphate, would be the proper anti¬ 
dote. The sulphuric acid would unite with the baryta of the poisonous 
salt, and form the harmless sulphate of baryta. 

690. Sulphate of Lime . This salt is abundant, existing in the 
form of gypsum, plaster stone, (called also plaster of Paris,) al¬ 
abaster, and silky crystals called selenite . It is found in the ash¬ 
es of plants, and the water of springs, causing what is called the 
hardness of the latter. Hard water, or that which contains salts, 
and consequently acids in solution, decomposes soap, while the 
oil combining with the earthy base of the salt, floats on the sur¬ 
face of the water ; thus it is impossible to form, what the laun¬ 
dress calls suds , with hard water. Add soap to a solution of sul¬ 
phate of lime, and the soap will immediately be decomposed. 

Sulphate of lime may be formed by adding sulphuric acid to 
any carbonate of lime, or lime water ; or mixing a solution of 
muriate of lime with any soluble sulphate. When pure it is 
perfectly white, as in alabaster. Exposed to intense heat, it loses 
its water of crystalization, and fuses into a white powder; in 
this state it forms plaster of Paris. 

Anhydrous sulphate of lime consists of 

one proportion of acid=40 
one do. of lime=28 

The compound equiv. is, therefore=68 

*Silliman’s El. Vol. 1. p. 325. 


689. Sulphate of baryta. Why not poisonous. 

690. Existence of sulphate of lime in nature. Hardness of water. 
Preparation of sulphate of lime. Plaster of Paris. Composition of anhy¬ 
drous sulphate of lime. Of the crystalized sulphate. Anhydrite. Uses 
of sulphate of lime. Plaster casts. 

26 * 




302 


INORGANIC CHEMISTRY. 


The crystalized sulphate contains, in addition, two proportions of water, 
=18, making its equivalent 68 added to 18=86. 

The uses of sulphate of lime are various. It is employed as 
a manure for soils ; and with lime plaster to give it a greater du¬ 
rability, firmness, and smoothness; this composition for walls 
and ceilings is called hard finish This is a great improvement 
upon the old .method of plastering, as it will bear washing with 
soap and water. Sulphate of lime is much used for statuary. 
Plaster Casts are often taken from persons after death,but with the 
faithful preservation of their lineaments. There is also, in such 
busts, but too accurate a delineation of that last repose, which, 
however sanctified by religious hopes, humanity yet shudders to 
contemplate. 

691. Sulphate of Magnesia was first obtained from a mineral 
spring, at Epsom, England ; hence its common name, Epsom 
salts. It is less bitter than the sulphate of soda, which it resem¬ 
bles in taste and medicinal properties. It is sometimes called 
Seidlitz salts , from a village in Bohemia w r hich contains mineral 
springs strongly impregnated with this salt. It exists in sea¬ 
water, from which it may be obtained by evaporation. It is also 
manufactured from magnesian lime stones. It is found crystal¬ 
ized in large quantities in limestone caverns in Kentucky and 
several other of the Western States. 

692. Sulphate of Alumina exists in nature in a mineral called 
aluminate. It may be formed by mixing alumina with sulphu¬ 
ric acid. The pure sulphate is of little importance ; but com¬ 
bined with sulphate of potassa it forms a double salt of alumine 
and potash; which is the common alum of commerce. This 
salt has an astringent taste, is soluble in water ; reddens infusions 
of purple cabbage slightly ; changes blue infusions from the pe¬ 
tals of flowers to a green color. 

If a frame work of strings, sticks, or wires be suspended in a 
vessel filled with a hot, concentrated solution of alum, large and 
beautiful crystals will collect upon the frame, and thus may be 
formed a variety of pretty ornaments, as baskets, vases, and flow¬ 
ers. Alum crystals contain half their weight of the water of 
crystalization. When heated, they .melt in this water, swelling 
and frothing, while the water passes off, leaving anhydrous alum 
in a white, light, and spongy mass. When heated with sugar, 
alum forms a compound which inflames spontaneously ; it is 
known as Homberg^s'pyrophorus. The sulphate of alumina corn- 

691. Sulphate of magnesia. 

692. Sulphate of alumina. Alum. Crystals of alum. Action of heat. 
Homberg’s pyrophorus. Combinations of the sulphate of alumina with 
sulphates of soda and ammonia. Composition of sulphate of alumina. 
Law of chemical combination illustrated by this salt. Uses of alum, &c. 



SULPHATE OF IRON. 


303 


bines with sulphate of soda and with sulphate of ammonia, form¬ 
ing double salts, which resemble, in most of their properties, the 
common alum. Native soda alum is found in South America 
and in Greece. 

The chemical equivalent of pure sulphate of alumina is stated at 58 ; 
and the composition of alum is as follows; 

Sulphate of potassa, 1 equivalent, =88 

Sulphate of alum, 3 equivalents, (58 X 3)=174 
Water, 25 equivalents, (9 X 25) 225 

Chemical equiv. of Sul. alumina and pot.=487 
The composition of this salt illustrates an important law of chemical 
combination, viz ; that, in the double sulphates, the quantity of oxygen 
in one of the bases will be proportioned to the quantity of oxygen in the 
other base. Now the oxygen in potassa is in proportion to the oxygen of 
alumina as 1 to 3; therefore there are three equivalents of alumina to 
one of potash in alum, or each base furnishes to the common stock an 
equal amount of oxygen. 

Alum is an important article of commerce, and is employed in 
medicine and the arts ; it is used in dyeing, calico printing, in 
paper manufactories and by tallow chandlers to render their tal¬ 
low more solid. It is not common in nature, but its elements 
are abundant. Where it is already formed, as at Solfaterra near 
Naples, it is sufficient to lixiviate* the earths, which contain it, 
and crystalize the liquor. 

693, The sulphates which are formed by the union of sulphu¬ 
ric acid with the fixed alkalies and alkaline earths, are the most 
important species of the genus sulphate . Those sulphates which 
are formed with the oxides of metals having neither earthy nor 
alkaline properties, and therefore commonly called metallic oxides , 
are scarcely less numerous than these oxides, since aU have 
some affinity more or less for sulphuric acid. But it should be 
remembered, that, in principle, there- is no distinction between 
alkaline, earthy, and metallic salts, since all salts, with the excep¬ 
tion of those of ammonia and the vegetable bases, which we shall 
h 3 reafter consider, are composed of acids and metallic oxides. 
Thus potassa and soda are now known to be oxides of metals, no 
less than the oxides of iron and copper ; though the two former 
are usually called alkalies, and the two latter metallic oxides. 

694. Sulphate of Iron. Sulphuric acid combines with three 
oxides of iron ; but according to Berzelius there are but the 

*To leach them, or to form a ley of them. 


693. Most important species in this genus of salts. Salts which are 
not based on metallic oxides. 

694- Number of combinations of sulphuric acid with oxides of Iron. 
Proto-sulphate of iron, or copperas, &c. 



304 


INORGANIC CHEMISTRY. 


proto and the jper-sulphates. He regards the deuto-sulphate as a 
compound of the two others. 

The proto-sulphate or sulphate of the protoxide of iron is com¬ 
monly called copperas , green vitriol, &c. It may be formed by 
the action of dilute sulphuric acid on metallic iron. Water is 
decomposed and furnishes oxygen, which uniting with the met¬ 
al forms the protoxide or salifiable base, hydrogen escapes with 
effervescence, and sulphuric acid unites with the newly formed 
oxide. This sulphate is seldom found in nature in a solid state ; 
but as the sulphuret of iron is abundant, and is changed by con¬ 
tact to a proto-sulphate, the latter is often found, in solution, in 
water flowing in the neighborhood of mines. 

The expense of evaporating these waters is such, that, for purposes 
of commerce, the proto-sulphate is usually obtained bj exposing the sul¬ 
phuret to the action of air and moisture ; sulphur, attracting oxygen be¬ 
comes sulphuric acid, and in this state enters into a new combination 
with the iron, forming the proto-sulphate. This salt crystalizes in 
rhombic prisms, is of a beautiful green color, and inky taste. Its color 
is owing to its water of crvstalization of which it contains 45 parts in 
100 of its weight. When deprived of this water by heat, it becomes of 
a dirty white color. This salt is useful in the arts, particularly in that 
of dyeing. In combination with nut-galls it forms ink. 

Persulphate of iron is formed by the action of nitric acid with the 
proto-sulphate, or by the action of sulphuric acid upon the red oxide of 
iron, slightly moistened with water. It is not crystalizable. 

The proto sulphate is composed of 

Sulphuric acid. 1 equivalent,=40 
Protoxide of iron, 1 do. 36 


Its combining equivalent is =76 

695 % The persulphate (or sulphate of the peroxide of iron) has 1 1-2 an 
equivalent, or 60 parts of sulphuric acid, with 1 equivalent of peroxide of 
iron. This furnishes a striking instance of the acid of a salt being in 
proportion to the oxygen of the base ; the more remarkable as the pe¬ 
roxide of iron has its half equivalent of oxygen, and we find it requir¬ 
ing an additional half equivalent of the acid for its saturation. 

696. Sulphate of manganese appears in transparent crystals of 
a slight rose tint. 

Sulphate of zinJc or white vitriol reddens blue vegetable colors, 
though in its composition it is a neutral salt, consisting of one 
equivalent of acid and one of oxide. It is obtained in granular 
masses, resembling sugar ; but by evaporation may be crystal- 
ized in quadrangular prisms. It is employed in medicine, as an 
astringent, and was formerly used as an emetic. 


695. Per-sulphate of iron. 

696. Sulphates of manganese and zink. 





SULPHATE OF COPPER. 


305 


697. Sulphate of Copper. There is no sulphate of the pro¬ 
toxide of copper ; for, according to Proust, when this protoxide 
is heated with sulphuric acid, the result is a solution of the 
deutoxide of copper, and a precipitate of metallic copper, which 
appears as a red powder.— Thenard. The bi-sulphate of copper 
(sulphate of the deutoxide) is the blue vitriol of commerce. 

It crystalizes in prisms with an oblique base ; its crystals contain in 
large quantities the water of crystalization, which renders them trans¬ 
parent, and gives them a beautiful blue color. Exposed to the air they 
become slightly efflorescent, and are covered with a whitish crust. They 
fuse easily in their water of crystalization, and become white. This salt 
has a strong metallic taste, is used in medicine as a caustic, and when 
taken into the stomach excites nausea. It is soluble in water, but not in 
alcohol. It is seldom found crystalized in nature; but, by evaporating 
the water of copper mines,* in which this salt exists in solution, the 
crystalized blue vitriol of commerce is obtained. The same substance is 
also prepared by roasting copper pyrites with access of air and moisture, 
the sulphur is acidified, the copper oxidized, and the deuto-sulphate which 
is formed, is extracted by solution and crystalization. 

Anhydrous sulphate of copper consists of 

Peroxide of copper, 1 equiv. = 80 

Sulphuric acid, 2 do. = 80 

Compound equivalent, = 160. 

The crystalized sulphate contains in addition 

10 equivalents of water = 90 

The equiv. of the crystalized sulphate is = 250 

The sulphate of copper reddens vegetable blue colors ; it is therefore 
called a super-sulphate, and sometimes a bi-per-sulphate. Silliman justly 
remarks :t “ The refinements of a significant nomenclature are some¬ 
times embarrassing, requiring frequent changes with the progress of dis¬ 
covery, and presenting names which are inconveniently long; they also 
compel us to return occasionally to the old proper names, such as alum, 
common salt, white, green, and blue vitriol.” To this remark we would 
add, that our Chemists have undoubtedly gone too far in attempting to 
introduce technical names into common language. Our respect for 
science would scarcely prevent a smile should we hear one call for the 
protoxide of hydrogen combined with hydro-carbonous oxide, instead of 
water and sugar. 

When ammonia is added to a solution of blue vitriol, a pre¬ 
cipitate appears, of a greenish blue color; on adding an excess 
of ammonia, this precipitate is dissolved and forms a liquid of 

* Copper ore usually contains some sulphur ; copper pyrites is the sul- 
phuret of copper. 

t Elements, Vol. II. p. 282. 


697. Sulphate of the protoxide of copper. Bi-sulphate of copper 
Blue vitrioh Composition of the anhydrous sulphate of copper, and the 
crystalized copper. Properties. Chemical names not adapted to com¬ 
mon language. Blue vitriol with ammonia. Uses of sulphate of copper 
in the arts. 





306 


INORGANIC CHEMISTRY. 


a beautiful blue color, called celestial blue ; it is the ammoniuret 
of copper. Ammonia affords a valuable test of copper. The 
sulphate of copper is used in the arts to prepare two colors, blue 
cinders , used in coloring paper, and Scheele's green. 

698. Sulphites. Salts of this sub-genus are formed by the union 
of sulphurous acid with salifiable bases. They are distinguished 
by a disagreeable taste, and an odor like that of burning sul¬ 
phur. When exposed to air and moisture they absorb oxygen, 
and pass to the state of Sulphates. They are decomposed by the 
stronger acids, such as the sulphuric, muriatic, phosphoric and 
arsenic ; effervescence takes place, owing to the escape of sul¬ 
phurous acid; and a sulphate is formed. Nitric acid, by yielding 
oxygen, changes the sulphites into sulphates. 


LECTURE XXIX. 

SALTS OF THE OXACIDS CONTINUED. 

GENUS II.-NITRATES. 

699. The nitrates may be formed by the action of nitric acid 
on metals, or their oxides. In the former case, according to the 
theory of the formation of salts, the metal must first oxidize, 
before it will become a salt. The nitrates are acted upon by 
sulphuric acid , which disengages nitric acid in the form of dense, 
white acid vapors, having the peculiar odor which distinguishes 
nitric acid. They are all decomposed by heat, giving out oxy¬ 
gen and becoming nitrates. By a strong heat they lose all their 
acid. When heated with charcoal or other combustible substan¬ 
ces, they suffer a sudden combustion, with an explosion and 
detonation. The process for oxidizing substances with nitrates 
is called deflagration. 

Most of the nitrates are composed of one equivalent of acid, and one of 
a protoxide ; the oxygen of the oxide and acid is, in these cases, in the 
ratio of 1 to 5, because the proportion of oxygen in the protoxide is 1, 
and in the nitric acid 5. The oxides of those metals which have the least 
affinity for oxygen, as gold, palladium, <fcc. part with their oxygen at a 
low temperature, and the nitrates formed with them are easily decom¬ 
posed, while the nitrate of lead and some others, require a red heat for 
their decomposition. 


698. Sulphites. 

699. Nitrates. 






NITRATE OF POTASSA. 


307 


700. titrate of Potassanitre , saltpetre , &c. exists in great 
quantities, in nature. It is not found in large masses, but dif¬ 
fused on the surface of the earth, usually in connection with the 
nitrates of lime and magnesia, in places where animal substances 
have suffered decomposition. Efflorescences of this salt, resem¬ 
bling mould, are found upon the damp walls of old cellars and 
subterranean buildings, especially when these walls are covered 
with lime mortar. Nitre is manufactured by lixiviating the sub¬ 
stances in which it is contained, and evaporating the solution. In 
the East Indies it is abundant as a natural production ; and large 
quantities are imported from thence into Great Britain and the 
United States. In Italy and Spain it is found in the dust of the 
roads ; and it is common in the grounds near Lima in South 
America. It exists in some plants, as the hemlock, sunflower, 
tobacco, &c. 

It is a white substance with a cool and sharp taste, and deflagrates 
when thrown upon burning charcoal. With heat it suffers the igneous 
fusion, as it contains no water of crystalization, though its crystals are 
not quite free from some water of interposition, or water lodged mechani¬ 
cally in their interstices, instead of being chemically combined with their 
particles. The crystals are six sided prisms, with wedge-shaped summits. 
Nitre is used in chemistry as a deoxidizing agent, and to obtain oxygen,t 
and nitric and sulphuric acids. The latter acid is obtained by heating 
nitre slowly with sulphur, in a leaden chamber, the floor being covered 
with water. It is useful in medicine on account of its cooling properties. 
It is an anti-septic, and is used in the salting of meat, to which it imparts 
a fine color, rendering the fibre both tender and compact. It is used in 
medicine in small quantities; large portions are hurtful. 

From its resemblance to Glauber's salts it is sometimes sold for that 
article. It can be known by its deflagrating on burning coals, and by the 
disengagement of the fumes of nitric acid, when tested with sulphuric 
acid. Owing to its rapid combination with water, it forms with ice a 
valuable freezing mixture. 

701. Its action with combustibles constitutes its efficacy as an ingredi¬ 
ent in gun powder, which is a mixture of 75 parts of nitre, 10 of sulphur , 

* The nitre of the scriptures is the carbonate of soda called in Greek, 
natron, and in Latin nitruin. Thus in Prov. 25 : 20, “ as vinegar upon 
nitre, so is he that singeth songs to a heavy heart." Here the efferves¬ 
cence or disturbance caused by the action of the acid vinegar upon the 
carbonate is evidently alluded to. In Jeremiah 11 : 22, we read of 
washing with nitre ; the cleansing or detergent property of the carbon¬ 
ate of soda must be referred to. 

t Oxygen being driven from nitre by heat, may be collected over the 
pneumatic cistern. 

700. Nitrate of potassa as found in nature. Manufacture of nitre. In 
what countries most abundant. Exists in plants. Properties. Action 
with heat. Crystals. Uses. Tests. Action with water. 

701. Gunpowder. Its composition. Discovery. Cause of its com¬ 
bustible nature. Cause of its explosive property. Force. Products of 
its detonation. Fulminating powders. 





308 


INORGANIC CHEMISTRY. 


and 15 of charcoal. These are the usual proportions, but they are some¬ 
times varied. The composition of gun-powder was discovered by Roger 
Racon, a friar, in the fourteenth century. It is supposed that the Chinese 
were previously acquainted with it. It was first used by the English at 
the battle of Agincourt in 1415. Gun powder is merely a mechanical 
mixture, as at common temperatures no chemical action takes place 
among its parts. But when heated, the oxygen which the nitric yields 
so readily and abundantly, acts on the carbon and sulphur, producing 
with the latter a rapid and violent combustion, while the former yields a 
large proportion of elastic vapor. The volume of gas produced from 
powder at the moment of explosion, is said to be 1000 times greater than 
that of the solid powder. As each additional volume of gas exerts a fore 
equal to that of the atmosphere, which is 15 pounds to the square inch, 
the force ofthis elastic vapor will be 1000X15=15,000 pounds on a square 
inch; this according to calculation will project a bullet with a speed of 
2000 feet in a second. The products of the detonation of gunpowder, are 
both gaseous and -solid ; the former consisting of mixtures of nitrogen, 
nitric oxide, carbonic acid, sulphuretted and carburetted. hydrogen and 
ammonia. The solid products are some sulphate, and sulphuret of po- 
tassa, carbonate of potassa and charcoal. 

Various fulminating 'powders are made with nitre, some of which pro¬ 
duce a more powerful detonation than gun powder. 

702. The composition of nitrate of potassa is, 

Nitric acid, 1 equivalent 54 

Potassa, 1 “ 48 


Combined equivalent, 102 

Or stating its elements thus, 

Ox. 5 equiv. 5x8=40 added to 1 equiv. Nit. 14=54, 

Pot 1 “ 40X1=40 addefi to 1 equiv. Ox. 8=48, 


The equivalent number of Nitre is, therefore, 102 

703. Nitrate of Silver is obtained by dissolving silver in nitric 
acid. This nitrate cast in small moulds, forms the lunar caustic* 
or lapis infernalis of medicine. It is highly corrosive, and chang¬ 
es the skin, first yellow, and then black on exposure to the air, 
(owing to the decomposition of the oxide of silver.) These 
stains are indelible, remaining till the cuticle, or scarf skin wears 
off. In a very dilute state it is used, with other ingredients, for 
staining the hair black, and for the indelible ink , so valuable for 
marking linen. 

An imposition has heretofore been practiced by the venders of the 
marking ink, by selling at a great price, a vial of what they call solution ; 
which is merely a solution of pearlash and water. The article to be 
marked, is first wet with this solution, and then dried, and smoothed with 

* Lunar is derived from the ancient name of silver, caustic , from its 
agency in destroying animal texture. The name lapis infernalis , or 
infernal stone , was given in allusion to its strong burning property. 


702. Composition of the nitrate of potassa. 

703. Nitrate of silver, how formed? Lunar caustic. Indelible ink. 
Mode of marking with this ink. Composition of nitrate of silver. 





NITRATES. 


309 


the flatiron, when it is ready for writing upon with the ink. The ink is, 
at first, a colorless liquid, (unless a small portion of India ink be added to 
it;) but the alkali of the pearlash, seizes the nitric acid, and forms ni¬ 
trate of potash; the oxide of silver being liberated, is precipitated among 
the fibres of the linen. Exposure to light, partially decomposes the 
oxide of silver, and the letters become black. When a white garment has 
been accidentally stained with this ink, the spot may be removed by 
steeping in nitric acid. 

Nitrate of silver is composed of 

Nitric acid, 1 equivalent = 54 
Oxide of silver, 1 do =118 

Its chemical equivalent is —172. 

704. Nitrites and Hypo nitrites. 

When nitrous acid is brought in contact with a salifiable base, 
the result is a nitrate , and a hypo , or sub-nitrate. It seems that 
nitrous acid is not susceptible of a permanent union with salifia¬ 
ble bases. By exposing the nitrates to a red heat, nitrites are 
formed ; but by exposure to the air, the latter absorb oxygen, 
and again become nitrates. The hypo-nitrites , contain, as their 
name implies, a less portion of oxygen than the nitrites. They 
lose their acid by heat, which are decomposed into oxygen and 
nitrogen. They are decomposed by water even at the ordinary 
temperature. 

GENUS III.—CHLORATES. 

705. These salts were formerly called Hyperoxy-muriates. 
They are formed by the combination of bases with chloric acid. 
They are analogous to nitrates, exploding by friction, or percus¬ 
sion, when mixed with sulphur, phosphorus, and other combus¬ 
tibles. They deflagrate with even greater violence than the 
nitrates, yielding oxygen so readily, that the slightest agitation 
will produce their explosion. They are decomposed by heat, 
giving off oxygen, and becoming metallic chlorides. They are 
soluble in water. Most of the .chlorates are composed of one 
equivalent of chloric acid, and one of a protoxide ; it follows, 
therefore, that the oxygen of the latter, to that of the former, is 
in the ratio of 1 to 5, (chloric acid having five proportions of ox¬ 
ygen.) None of the chlorates are found native. They were dis¬ 
covered by Berthollet, in 1786. 

706. Chlorate of potassa , or Hyper-oxy-muriate of potash is the 
most important species of the chlorates. 

704. Results of the contact of nitrous acid with a salifiable base. 
Change of nitrates to nitrites, &c. Hypo-nitrites. 

705. Former name of chlorates. Formation and character. Decom¬ 
position. Composition of the chlorates, &c. 

706. Importance of chlorate of potassa. How formed ? Rationale of 
the process. What other theory explains the formation of chlorate of 
potassa in the manner which has been described ? 

27 



310 


INORGANIC CHEMISTRY. 


It may be formed by passing a stream of chlorine gas, through a solu¬ 
tion of caustic potash in Woulfe’s bottles, or by saturating the gas with 
a solution of potash. A, represents the outer one of three jars, contain¬ 
ing solution of the sulphate of potash; peroxide of manganese being put 


Fig. 109. 



into a retort and some muriatic (hydro chloric,) acid added to it, chlorine 
gas is disengaged, and passes through the neck of the retort to the globe 
JB^from whence it proceeds through the trumpet shaped tube, into the 
inner jar. If it be not all absorbed by the liquid in this jar, the super¬ 
fluous gas will escape into the next, jar, and so on, until all the liquid is 
saturated ; any gas which remains in excess, is conducted off hy the pipe 
P, and received in an inverted bell glass. E is a pipe which, when ex¬ 
tended, may Still further serve for conducting off the superfluous gas, 
into a suitable receiver. 

In this operation, it is supposed that one part of the potassa is deoxi¬ 
dized, and the reduced metal uniting with chlorine forms the chloride of 
the potassium, which is in solution ; the oxygen of the potash unites to 
another portion of the chlorine, and produces chloric acid, which, com¬ 
bining with the undecomposed potassa, forms the chlorate of potassa. 

Another theory accounts for the formation of this salt, by supposing 
that the water of the solution of potassa is decomposed to furnish oxygen, 
which uniting with chlorine forms chloric acid, and this acid combines 
with a part of the base, to form chlorate of potassa; and that the hydro¬ 
gen of the water, uniting with a portion of disengaged chlorine, forms 
muriatic (hydro-chloric,) acid; and the latter with a portion of the po¬ 
tassa, forms muriate, (hydro-chlorate,) of potassa. Upon this theory, the 
potassa is not decomposed, but is divided between the muriatic and chlo¬ 
ric acids, which are both formed by means of the decomposition of 
water 










CHLORATE OF POTASSA. 


311 


707. In the saturated solution 
Fi°\ 110 of c ^ ora t e of potassa, there is a 

large proportion of muriate of po¬ 
tassa, with some siliceous earth, 
which had existed with the alkali. 
The muriate of potassa being more 
soluble in water than the chlorate, 
the precipitated and crystalized 
salt should be re-dissolved in hot 
water, filtered and crystalized 
again. It is necessary to keep the 
solution hot, while filtering, for 
which purpose, Dr. Hare contriv¬ 
ed the apparatus here represented. 
A large vessel of sheet tin was 
fitted to a tin funnel, to support a 
glass filtering funnel, and is fur¬ 
nished with an aperture which 
serves the purpose of a chimney, 
by conducting off the smoke of 
the argand lamp below. This 
lamp keeps the water hot, with 
which the tin vessel is filled. The 
hot water thus surrounding the so 
lution as it filters, prevents its 
cooling. A coarse fibrous paper for a filter, is placed within the funnel; 
the filtering solution of chlorate of potassa, is received in the decanting 
jar beneath, then the salt crystalizes in beautiful white, rhomboidal 
scales, resembling mother of pearl. Their taste is cool, but bitter and 
nauseous. The crystals are anhydrous, and suffer the igneous fusion, 
below red heat; at a higher temperature they give off oxygen, with boil¬ 
ing and effervescence, and become chloride of potassium. 

708. Chlorate of potassa yields a large proportion of pure ox¬ 
ygen gas. For this feason it acts powerfully on combustibles, 
readily inflaming them and producing violent detonation. Two 
parts of chlorate of potassa mixed with one of sulphur, and put 
into a paper will explode with great violence on being struck 
with a hammer. When rubbed in a mortar with phosphorus or 
charcoal, a loud detonation and jets of fire are produced. 


707. Mode of purifying the saturated solution of chlorate of soda 
Explain the construction, and mode of using Dr. Hare’s apparatus for 
conducting this process. Crystals of chlorate of potassa. Action of heat 
upon the crystals. 

708. Cause of the effects of chlorate of potassa, on combustibles. 
Chlorate of potassa with sulphur. With phosphorus and charcoal. 
Experiment. 
































312 


INORGANIC CHEMISTRY. 


If a small portion of phosphorus covered by chlorate of 
potassa, be placed in a glass which is then filled with 
water and sulphuric or nitric acid, poured in through a 
long glass funnel, the mixture is inflamed, and burns 
with great brilliancy, with a series of detonations. Sugar 
mixed with chlorate of potash, deflagrates with the ad¬ 
dition of a small quantity of sulphuric acid. 

709. Chlorate of potassa is used in Chemistry to obtain 
pure oxygen gas, and oxide of chlorine to oxidize metals 
and combustibles, and to analyze vegetable compounds. 
In the arts, it is used flor fire matches, and attempts have 
been made to introduce it as an ingredient in gun-pow¬ 
der ; but, though it produces a powder of greater im¬ 
pelling force than that which is commonly used, it in- 
y by slight friction, or shocks, that its manufacture and 
use are very dangerous, and prevent its being employed for this purpose. 

It is composed of 

Chloric acid 1 equivalent = 76. 

Oxide of pot. 1 do = 48. 

Chemical equiv., therefore = 124 

Its ultimate compounds being 6 proportionals of oxygen, 5 in the acid, 
and 1 in the alkali, 6 X 8 = 48 
1 proportion of chlorine = 36 
1 do potassium == 40 

Compound chemical equiv. = 124 

710. Per-chlorates or oxigenated chlorates , are formed by the 
union of per-ehloric acid with salifiable bases. These salts 
w'ere discovered by Count Stadion. They are little known. 

GENUS IV.-IODATES. 

711-. The iodates are the product of art, either by combining 
iodic acid directly with bases, or by double decomposition. The 
composition of iodic acid being similar to chloric acid, in re¬ 
spect to the quantity of oxygen, the iodates, like the chlorates, 
contain oxygen in the oxide and acid in the proportion of one to 
five. Like the chlorates these salts form deflagrating mixtures 
with sulphur, charcoal and other inflammables, by a ready dis¬ 
engagement of oxygen. Most of the acids decompose the io¬ 
dates, by attracting the oxygen from iodic acid. The iodate of 
potassa is the most important species of this genus. 


709. Uses of chlorate of potassa. Cause which prevents its being used 
in gun-powder, Composition. 

710. Per-chlorates. 

711- Remarks on the genus, iodates. 


Fig. 111. 



flames so easi 





BROMATES. PHOSPHATES. 


313 


GENUS V.-BROMATES. 

712. Like chlorates and iodates, the proportion of the oxide 
to the acid in the bromates, is in the ratio of 1 to 5, bromic acid 
containing 5 proportions of oxygen. The properties of the bro¬ 
mates.appear to be analogous to those of chlorates, and iodates. 

GENUS VI.-PHOSPHATES. 

713. These salts are not decomposable by heat, but melt at a 
high temperature. They are extensively diffused in nature. 
The phosphate of lime is most abundant, often forming an impor¬ 
tant constituent of mountain masses, and existing largely in ani¬ 
mal bones. There are phosphates with excess of base, (called 
alkaline phosphates ,) neutral phosphates , acidulated phosphates , 
and acid phosphates. 

714. Phosphites are a combination of phosphorous acid with 
salifiable bases. When exposed to heat, they disengage phos- 
phuretted hydrogen, and a little phosphorus, while a phosphate 
colored by the oxide of phosphorus remains. When thrown 
upon burning coals, they produce a yellow flame. Hypo-phos¬ 
phites are combinations of hypo-phosphorous acid with bases. 
They are too soluble to be crystalized. 

GENUS VII.-ARSENIATES. 

e J* * % 

715. Salts composed of arsenic acid with bases are called 
arseniates. 

Arsenites are combinations of arsenious acid with bases. 
They are distinguished from the arseniates by a green precipi¬ 
tate with sulphate of copper, while the arseniates form with the 
same compound a bluish white precipitate. The arsenite of 
copper is Scheele’s green. The arsenite of potassa is known 
in medicine as Fowler’s solution. 

GENUS VIII.-CHROMATES. 

716. The salts which result from the union of chromic acid 


712. Bromates. 

713. Phosphates. 

714. Phosphites. Hypo-phosphites. 

715. Arseniates. Arsenites. 

716. Character of the chromates. Chromate of lead. Chromate of 
lime. Chromate of potassa, &c. Chromates of silver and copper. 

27 * 



314 


INORGANIC CHEMISTRY. 


with salifiable bases, are all colored ; yellow and red are the pre¬ 
vailing colors, the latter appearing when there is an excess of 
acid. The chromate of lead is a brilliant yellow, known in the 
arts as chrome yellow, and a beautiful pink in the state of a sub¬ 
salt. Chromate of lime is yellow ; it is prepared by adding the 
chromate of lead to the hydrate of lime. Chromate of potassa 
is of a lemon color; at a high temperature, part of its acid de¬ 
composes. Potassa ean combine with an excess of chromic acid, 
in which case the salt is of intense orange color. The other 
chromates are usually obtained by the decomposition of chro¬ 
mate of potassa. Chromate of silver is of a rich crimson color. 
Chromate of copper is apple green. 

GENUS IX.'-BORATES. 

717. Boracic acid is reckoned among the weak acids ; its salts 
are therefore readily decomposed by the greater attraction of oth¬ 
er acids for their bases. The Borates dissolve in alcohol, and 
burn with a green flame. Bi-borate of soda is imported from the 
East Indies in a crude state under the name of tincal. This is 
purified in the substance known in the arts as borax. It has 
been ealled the sub-borate of soda, because it possesses alkaline 
properties ; but it is composed of two equivalents of boracic 
acid, with one equivalent of soda ; its crystals have in addition 
eight equivalents of water. When exposed to heat, the crys¬ 
tals lose their water of crystalization, and then become fused, 
forming a vitreous substance called glass of borax. Its chief 
use is in chemistry for the preparation of boracic acid; in the 
arts of glass making and pottery, as a flux. 

GENUS X.-CARBONATES. 

718. These salts effervesce with sulphuric acid, which, uni¬ 
ting with their bases, disengages carbonic acid. The efferves¬ 
cence is caused by the escape of the latter acid. When exposed 
to a high heat they lose their carbonic acid. Some of them, as 
the carbonate of baryta, are not decomposed but at a very intense 
heat; but this operation may be facilitated by heating them with 
charcoal. The carbonates of the alkalies have afi alkaline taste, 
and change to green the vegetable blue colors ; those, of the 
earths are insoluble, but become soluble with an excess of car¬ 
bonic acid. Many of the carbonates are found in nature. 

717. Character of the borates. Bi-borate of soda. Crystals. Glass 
of borax. 

718. Character of the carbonates. 




CARBONATE. 


315 


719. Carbonate of potassa, is not found in nature, but is ob¬ 
tained by lixiviating vegetable ashes, and evaporating the solu¬ 
tion to dryness. Pearlash or saleratus differs from the crude 
carbonate of potash only in being freed from impure matter. 
The use of this salt in various culinary operations is well known 
to every house keeper. Its action with flour in raising bread, 
buiscuits, &c. depends on the readiness with which it disengages 
carbonic acid, which becoming entangled among the glutinous 
particles of the paste, tends to make a light and spongy mass. 
On its alkaline properties depends its utility in neutralizing the 
sourness produced by suffering the dough to remain unbaked, 
until the vinous fermentation changes to the acetous. Some 
housewives prefer to- let their dough thus sour, as, by adding 
pearlash, bread and biscuit are rendered more spongy and tender, 
while the acidity may be wholly corrected. But this process, 
unless carefully conducted, will give to the bread a darker hue, 
and the peculiar taste of pearlash. With a little attention, how¬ 
ever, very delicate and palatable biscuit may be made without 
yeast, simply by the' action of pearlash and sour cream or milk 
mixed and kneaded with the flour, and baked immediately. The 
common pearlash is uncrystalized, and anhydrous. It exists in 
white porous masses. Potash is harder and of a darker color. 

720. Carbonate of soda , is obtained by lixiviating the ashes of 
marine plants. The soda of commerce is an impure carbonate, 
which may be purified by heat. Though alkaline, it is not high¬ 
ly caustic. Its solution forms beautiful crystals composed of 
two quadrilateral pyramids; They contain 10 equivalents of 
water, with 1 of carbonic acid and 1 of sodaor acid 1 equiv. 
=22 added to do, soda, 32, added to 10 do. water, 90=144, 
which is the equivalent of crystalized carbonate of soda. 

Bi-carbonate of soda is, in its composition analogous to the bi¬ 
carbonate of potassa. A sesqui-carbonate is said to exist native 
on the banks of soda lakes in Africa ; this in commerce is called 
trona. The best variety of the carbonate of soda which is known 
in commerce is called barilla; aw inferior kind is called kelp. 
These substances are much used in the manufacture of glass, 
soap, in-dyeing, bleaching, and in the preparation of artificial 
soda water. 

719. Carbonate of potassa, how formed ? Pearlash. 

729. From what plants is the carbonate of soda obtained ? Soda of 
commerce. Crystals. Composition of the crystals. Bi-carbonate. 
Sesqui-carbonate. Barilla and kelp. Their uses. 



316 


INORGANIC CHEMISTRY. 


721. Carbonate of ammonia^ commonly called volatile salts of 
hartshorn ; this is considered as a sesqui* carbonate , consisting of 
1 equivalent of ammonia, with 1 1-2 carbonic acid. It is pre¬ 
pared by heating muriate of ammonia with carbonate of lime ; 
double decomposition ensues, muriate of lime remains in the re¬ 
tort, and the sesqui carbonate of ammonia sublimes. This salt 
is the white substance contained in thje hartshorn smelling bot¬ 
tles ; they are prepared by receiving the sublimed vapor of the 
salt, which forms a crust or lining, by condensing on the sides 
of the vials. Its odor is volatile, pungent and stimulating to the 
nerves. It produces the alkaline effects on blue vegetable col¬ 
ors ; alkaline earths attract its acid and liberate ammonia, while 
the acids attract ammonia and liberate the carbonic acid gas with 
effervescence. The proper carbonate of ammonia , or that with 
one equivalent of acid and one of the base, js formed by ming¬ 
ling carbonic acid gas over mercury, with twice its volume of 
ammonia. 

Bi-carbonate of Ammonia is prepared by saturating a solution of 
the carbonate with carbonic acid gas. The common hartshorn 
or sesqui carbonate, when exposed to the air, loses ammonia and 
gains carbonic acid, and appears to be converted into a bi-car¬ 
bonate, becoming almost inodorous and tasteless. This salt is 
composed wholly of gases in a condensed state ; the acid consist¬ 
ing of carbon and oxygen, the base of hydrogen and nitro¬ 
gen ; or 

Acid, l equiv. carbon 6 added to 2 equiv. oxygen 16=22 
Base , 1 equiv. nitrogen 14 added to 3 equiv hydrogen 3=17 

The chemical equivalent of this salt is, therefore, 39 

As there are two equivalents of acid and one of base , the propor¬ 
tions are, carbonic acid 44 added to ammonia 17=61. The car¬ 
bonate of ammonia is a most valuable medicine. It is much 
used in chemistry as a re-agent, and, diluted with water, has its 
useful applications in domestic economy, in removing spots of 
oil or grease from cloth, &c. 

722. Carbonate of baryta may be prepared by double decompo¬ 
sition, by mixing a soluble salt of baryta with any of the alka¬ 
line carbonates. It is found native: is an insoluble salt, and of 

*The term sesqui signifies one and a half. 


721. Common name of the sesqui-carbonate of ammonia. Composi¬ 
tion. Preparation. Smelling bottles. Properties of the sesqui-carbon¬ 
ate of ammonia. The proper carbonate. Bi-carbonate. Composition. 
Uses of carbonate of ammonia. 

722. Carbonate of baryta. 




CARBONATES. 


317 


great use in chemistry for preparing the other salts of baryta. It 
is not readily dissolved by heat. 

723. Carbonate of Lime is an insoluble compound of lime, ex¬ 
isting abundantly in nature, in the form of lime stone, marble, 
chalk, alabaster, stalagmites, spar, &c. It is sometimes found 
crystalized, and in this state presents various modifications of the 
obtuse rhomboid. It is decomposible by fire, and by most 
of the acids, with effervescence. It is used in chemistry 
for obtaining pure lime, and carbonic acid, and in the arts for 
building and statuary. It is much used as a manure for soils, 
both in the form of lime and carbonate of lime. The advan¬ 
tage of burning it for this purpose appears to be of no other use 
than to destroy cohesion, so that it may be easily scattered 
among the soil; for quick lime soon becomes a carbonate by ab¬ 
sorbing carbonic acid from the atmosphere. It was discovered 
by Dr. Black, in 1756, that lime acquired its caustic properties 
by the loss of carbonic acid. Though insoluble in water, car¬ 
bonate of lime dissolves by an excess of carbonic acid : for this 
reason the spring water of lime stone countries is impregnated 
with this salt which is found deposited upon the bottom and sides 
of tea kettles, in which such water is boiled. 

724. Carbonate of Magnesia is prepared by decomposing sul¬ 
phate of magnesia by carbonate of potassa. It is not found pure 
in nature, being mixed with libne, silex, &c. Calcined magnesia 
is the carbonate deprived of its magnesia by heat. 

Carbonate of Iron ex ists in nature in masses and veins. It is 
contained in most mineral springs, being held in solution by per- 
carbonic acid. 

It may be prepared by decomposing the sulphate of iron by a solution 
of carbonate of soda or potassa. The precipitate of earbonate of iron 
readily attracts oxygen from the atmosphere, and the protoxide of iron, 
becoming a peroxide, parts with carbonic acid, which does not form with 
it a definite compound. Thus the carbonate of iron known in medicine, 
is chiefly the peroxide, distinguished by its red color. 

Carbonate of copjjer exists in nature as a beautiful light green mineral, 
called malachite , which is a carbonate of the peroxide of copper. It may 
be prepared by adding carbonate of potassa to nitrate or sulphate of cop¬ 
per. In an impure state it constitutes the blue pigment known as ver~ 
diter. 

Carbonate of Lead, whitelead , or ceruse. This substance, so much 
used in the arts, is rarely found in nature. It is manufactured by intro¬ 
ducing a current of carbonic acid gas into a solution of the acetate of 
lead. ° Another method is to expose thin plates of sheet lead to the vapor 


723. Carbonate of lime, as found in nature. Decomposition. Uses. 
The utility of burning it for manure. Dr. Black’s discovery. Solution 
of carbonate of lime. 

724. Carbonates of magnesia, lime, iron, copper and lead. 



318 


INORGANIC CHEMISTRY. 


of vinegar, which, by its acid fumes, first oxidizes the lead, and then 
changes it to a carbonate. 


LECTURE XXX. 

ORDER II.-SALTS OF THE HYDRACIDS. 

725. The term hydracid is exceptionable, as it may lead the 
pupil to infer that hydrogen performs the same office in the hy¬ 
dracid, as oxygen in the oxacid ; whereas it is the element with 
which hydrogen is united in these acids, that is, in reality, the 
acidifying principle, and analogous to oxygen ; thus chlorine and 
iodine, like oxygen, are supporters of combustion, while hydro¬ 
gen is a combustible body. Like oxygen, chlorine and iodine 
on the decomposition of hydro-chloric and iodic acids by galvan¬ 
ism go to the positive pole, being like oxygen negative in rela¬ 
tion to hydrogen. 

The acids in which hydrogen is a constituent element, and 
which form distinct genera of salts with different bases, are the 
following: 

Hydro-chloric, (muriatic acid ) 

Hydriodit. 

Hydi o-bromic. 

Hydro-fluoric, 

Hydro-sulphuric , (sulphuretted hydrogen.) 

Hydro-cyanic , (prussic acid.) 

GENUS I.-HYDRO-CHLORATES. 

726. These salts are composed of hydro-chloric acid, and me¬ 
tallic oxides. The name, muriatic acid, was first given to the 
hydro-chloric, on the supposition that it was composed of oxy¬ 
gen, and a base called muriatum; after the discovery of chlorine, 
and the consequent change of opinion with respect to the nature 
of muriatic acid, the name hydro-chloric, was given in con¬ 
formity with the principles of the new nomenclature, as this 
name expresses the constituent elements of the acid, while that 
of muriatic acid is wholly arbitrary, and unmeaning. Yet it had 
become so well festablished, and its compounds, the muriates and 

725. Difference in the nature of the office performed by the hydrogen 
and oxygen of these respective acids in the formation of salts. Num¬ 
ber of hydracids. 

726. Cause of the change of the name muriatic acid, to that of hydro¬ 
chloric. Why may chemical changes be better understood by using the 
proper chemical terms ? 








HYDRIODATES. 


319 


oxymuriates , so well known by these names, that custom has, in 
a measure, prevailed over the mandates of science, and the new 
nomenclature is often not even used by Chemists themselves. 
But in explaining the nature of these compounds, and the changes 
that take place in them, as they are at present understood, we 
shall be more intelligible by using the new nomenclature. For 
instance, when hydrogen or chlorine are spoken of, as being dis¬ 
engaged in the decomposition of a muriate , we cannot so readily 
comprehend the nature of the process, as if the muriate had been 
called by its more appropriate name, hydro-chlorate. 

727. Hydro-chlorates are intimately related to the chlorides, as in 
desiccation, (drying) and crystalization the hydrogen of the hydro-chloric 
acid unites with the oxygen of the oxide forming water, and leaving the 
chlorine unitbd to the metallic base of the oxygen, in other words, the 
hydro-chlorate has become a chloride. On the other hand, when the 
chlorides are dissolved in water, the chlorine unites with the hydrogen, 
and the metal with the oxygen of the water, and the newly formed hydro¬ 
chloric acid, and metallic oxide combine to form a hydro-chlorade. 
Thus dry common salt is chloride of sodium, but dissolved in wafer it is 
chlorate of soda. Dry hydro-chlorates or muriates, except that of am¬ 
monia, are mostly considered as chlorides. 

The hydro-chlorates differ from all other salts by forming the white 
insoluble chloride of silver, when mixed with the nitrate of silver, and by 
being decomposed at the common temperature by sulphuric acid, with 
effervescence, and disengagement of white pungent fumes, characteris¬ 
tic of hydro-chloric acid. They differ greatly from the nitrates in being 
little affected by charcoal, sulphur and other combustibles. They melt 
and volatilize by heat. They are soluble in water. The hydro-chlorates 
which are found in nature are ammonia, soda, lime, potassaand magnesia. 

728. Hydro-chlorate (or muriate) of ammonia , or the sal- 
ammoniac of commerce may be prepared by decomposing sul¬ 
phate of ammonia, with the hydro-chlorate of soda. The two 
gases ammonia and hydro-chloric acid exchange bases, and 
unite, forming the solid hydro-chlorate of ammonia, which is 
obtained pure by sublimation. 

Hydro-chlorate (or muriate) of soda is the chief constituent of 
sea-water ; it exists only in solution, for w r hen evaporated it be¬ 
comes chloride of sodium. Hydro-chlorate , (muriate) of potassa 
exists in solution in mineral springs. Hydro-chlorate of baryta 
is an important re-agent in chemistry. Hydro-chlorate , (muriate) 
of lime exists in mineral springs, and often gives common spring 
water the property called hardness , which is indicated by its not 
combining well with soap. Hydro-chlorate (muriate,) of mag¬ 
nesia is abundant in sea-water, and often exists in mineral 
springs. When hydro-chlorate of soda is separated from sea- 

727. Connection of the hydro-chlorates and chlorides. Peculiar 
properties of the hydro-chlorates. 

728. Hydro-chlorate of ammonia. Hydro-chlorates of soda, potassa, 
baryta, lime, and magnesia. 



320 


INORGANIC CHEMISTRY. 


water by crystalization, a liquid remains called Bittern , consisting 
mostly of hydro-chlorate of magnesia. 


GENUS lit - HYDRIODATES. 

729. The salts of this genus are formed by the action of hy- 
driodic acid with alkaline earths and metallic oxides; and are 
supposed to exist only in solution. In drying, the hydrogen of 
the acid, unites with the oxygen of the oxide forming water; 
iodic acid then unites with the metal, and an iodide remains. 
Hydriodic acid does not unite with all the metallic oxides ; it 
forms salts with the alkalies and alkaline earths, and with the 
oxides of zink, iron, and manganese. The hydriodates of potassa 
and soda are the only salts of this genus which are known to ex¬ 
ist in nature. They are formed in the water of mineral and salt 
springs, in sea-water sea-weed ; in the sponge and oyster, and in 
some other mineral, vegetable and animal substances. 

730. Hydriodate of potassa is more known than any of the 
salts of this genus. It may be prepared by adding hydriodic acid 
to potassa. On being crystalized, the oxygen of the potassa 
unites with the hydrogen of the acid to form water which evap¬ 
orates, while the iodic acid unites with the potassium and a solid 
iodide remains. 

GENUS III.-HYDRO-FLUATES. 

731. The salts of this genus are formed of hydro-fluoric acid 
united with bases. The nature of the acid, (see § 298,) is some¬ 
what doubtful. It was formerly Supposed to consist of Oxygen 
and fluorine ; but is now considered as a hydracid. The analo¬ 
gies of this acid with the hydro-chloric, are in some respects re¬ 
markable ; and these analogies extend to the salts of the two 
acids. Thus when the hydro-fluates are evaporated to dryness, 
they become fluorides , when the latter dissolve in w ater, they are 
hydro-fluates . 

Though the hydro-fluates give the alkaline test with vegeta¬ 
ble colors, they are, according to Berzelius and Thenard, neutral 
salts ; that is, composed of one equivalent of the acid with 
one of the base. It is not certain that they exist in nature, 
though the topaz has been called a double hydro fluate of silica 
and alumina y and some other rare minerals have been considered 


729. Remarks upon the hydriodates. 

730. Hydriodate of potassa. 

731. Remarks upon the hydro-fluates. 
nard. Fluor Spar. 


Opinion of Berzelius and The- 




hydrofluates. 


321 


as composed of hydro-fluoric acids united to metallic oxides. 
But these compounds are now regarded as fluorides. Fluor spar 
was known in chemistry as fluate of lime, when its acid was sup¬ 
posed to consist, in part, of oxygen ; but it is now regarded as a 
fluoride of calcium. 

732. Hydro-fluate of potassa. Two definite compounds of 
hydro-fluoric acid and potassa may be formed. The neutral 
hydro-jluate , consisting of one equivalent, and the bi-hydro-fluate , 
consisting of two equivalents of the acid to one of the base. The 
neutral hydro-fluate seems improperly named, since it possesses 
alkaline properties ; the bi-hydro-fluate gives the acid test with 
vegetable colors. The hydro-fluoric acid forms also, with soda 
an d ammonia, both neutral and acid salts. 

GENUS IV. 

733. Hydro-sulphurets or Hydro-sulphates. The term hydro- 
sulphuric acid , which is generally used by the French Chemists 
to designate the acid composed of hydrogen and sulphur, is more 
expressive of its composition than the name sulphuretted hydro¬ 
gen. In the one case the salts formed with the acid would be 
properly called, hydro-sulphates ; in the other hydro-sulphurets. 
This acid seems not capable of combining with the oxides of many 
of the proper metals, but forms with the alkaline earths soluble 
salts which have an acid and bitter taste, and disagreable odor. 

The composition of the hydro-sulphates is such that if the hydro-sul¬ 
phuric acid (or sulphuretted hydrogen) and the oxide mutually decom¬ 
pose each other, the result is, water and a metallic sulphuret correspond¬ 
ing to the degree of oxygen contained in the oxide; thus a protoxide 
will produce a proto-sulphuret, and a deutoxide, a deuto-sulphuret. 

“ Sulphuretted hydrogen being a weak acid and naturally gaseous, its 
salts are decomposed by most other acids, with disengagement of sul¬ 
phuretted hydrogen gas, a character by which all the hydro-sulphates 
are easily recognized. When recently prepared, they form solutions 
which are nearly colorless, but on exposure to the air, oxygen is absorb¬ 
ed, a portion of its acid is deprived of its hydrogen, and sulphuretted hy¬ 
dro-sulphate of a yellow color is generated. By continued exposure, the 
whole of the sulphuretted hydrogen is decomposed, water and hypo-sul¬ 
phurous acids being produced.”-— Turner. 

734. Hydro-sulphuret of ammonia is formed in nature by the decom¬ 
position of animal substances. It is obtained in the laboratory by com¬ 
bining ammoniacal gas with sulphuretted hydrogen gas at a very low 


732. Hydro-fluate of potassa. 

733. Synonyme of hydro-sulphuric acid. Name of the salts of this 
acid. Substances with which it it combines. Properties of the salts. 
Result of this decomposition. Why they are easily decomposed. So¬ 
lutions of the hydro-sulphurets. Effect of air upon these solutions. 

734. Hydro-sulphuret of ammonia. 

28 




322 


INORGANIC CHEMISTRY 


temperature; for this purpose the gases are often mixed in a glass globe 
surrounded by ice ; the salt will be deposited in the form of white 
scales. 

735. The hydro-sulphates of potassa, soda , baryta , strontia, lime and 
magnesia may be obtained directly, by causing a current of hydrogen 
gas to pass into solutions of these bases in water. For this purpose, an 
apparatus like that represented in figure 112 is used. 

Fig. 112. 



The matrass placed over a furnace contains sulphuret of antimony , the 
first flask water to wash the gas, and the third flask contains a solution 
of soda; more flasks may be added, containing solutions of other alka¬ 
lies or earths. Hydro-chloric acid is poured through the branching tube 
upon the sulphuret of antimony, and a gentle heat applied ; hydro-chlo¬ 
rate of the protoxide of antimony is formed in the matrass, while the 
sulphuretted hydrogen is disengaged ; as the gas ceases to pass over less 
freely ; new portions of acid are from time to time poured into the’matrass, 
until all the sulphuret of antimony is dissolved. The operation is complet¬ 
ed when sulphuretted hydrogen gas ceases to be absorbed by the alkaline so¬ 
lutions.* None of the sulphurets are employed in the arts. Their 
chief use is in chemistry as reagents. 

736. Bi-sulphuretted hydrogen , containing two equivalents of sulphur 
with one of hydrogen, unites with alkalies and alkaline earths forming 
salts which are called sulphuretted hydro-sulphurets. These salts may 

* This process is recommended by Thenard from whose Traite de Chi- 
mie , the figure is taken. 


735. Hydro-sulphates of potassa, soda, &c. Process for preparing 
these salts by means of a current of hydrogen. 

736. Bi-sulphuretted hydrogen. Dr. Hope’s eudiometer. 





















































HYDRO-SULPHURETS. 


323 


also be prepared by boiling sulphur in solutions ot 
the hydro-sulphurets. They absorb oxygen rap¬ 
idly from the air, and were therefore, used in eu- 
diometry. The figure represents the eudiometer 
of Dr. Hope. It consists of a graduated glass 
tube, sealed at one end, and at the other fitted, 
into the mouth of a tubulated glass bottle, so as 
to be air tight. The tube is filled with gas, the 
bottle with the liquid (the sulphuretted hydro-sul- 
phuret.) The tube under these circumstances, 
being inserted into the mouth of the bottle, the 
gas it contains is made to pass into the bottle by 
inverting both : the mixture is then agitated, and 
time allowed for the absorption to be completed. 
In the interim the tubulure is to be occasionally 
opened under water, by removing a ground stop¬ 
ple with which it is furnished. The gas absorbed 
is consequently replaced by water. The gradua¬ 
tion being inspected, the deficit produced by the 
absorption of oxygen is thus ascertained.”— Dr. 
Hare. 


GENUS V.-HYDRO-CYANITES OR PRUSSIATES. 

737. These salts are formed by combining hydro-cyanic acid 
(prussic acid) with bases. They are distinguished by the for¬ 
mation of a deep-blue precipitate with salts of the peroxide of 
iron. With salts of the protoxide they give an orange colored 
precipitate, changing in the air to green and blue. 

Hydro-cyanate of potassa may be formed directly, by the 
union of hydro-cyanic acid with potassa; or by the decomposi¬ 
tion of water by cyanuret of potassium ; in the latter case the 
oxygen of the water forms an oxide with potassium, and the hy¬ 
drogen forming hydro-cyanic acid with cyanogen. The acid 
and^oxide combined form the salt. Thus the cyanuret of potas¬ 
sium can only exist in the dry state, as when dissolved in water 
it becomes a hydro-cyanate. 

The cyanurets of the other alkaline and earthy bases also become hy- 
dro-cyanates when in solution; the phenomenon being analogous to that 
attending similar changes in the chlorides, iodides, bromides and fluo¬ 
rides. On the other hand, the hydro-cyanates, when evaporated become 


737. Characteristics of the hydro-cyanates. Hydro-cyanate of po¬ 
tassa. Change of cyanurets by solution. Evaporation of hydro-cyan¬ 
ates. Properties of the hydro-cyanates of potassa. 
























324 


INORGANIC CHEMISTRY. 


cyanurets, parting with hydrogen from the acids, and oxygen from the 
oxides which unite to form water. 

GENUS VI--HYDRO-FERRO CYANATES. 

738. These salts are sometimes called triple prussiates,ferro- 
prussiates , and ferro-cyanates. Hydro-ferro-cyanic acid, as its 
name indicates, consists of hydrogen, iron and cyanogen. It 
unites with oxides in the same manner as the other hydracids, 
the hydrogen of the acid being in the exact proportion to form 
water with the oxygen of the oxide. It forms soluble salts 
with the alkalies and alkaline compounds. When evaporated by 
heat, the hydrogen of the acid goes off with the oxygen of the 
oxide in aqueous vapor, and a ferro-cyanuret remains. 

739. Hydro ferro-cyanate of potassa or triple prussiate of po- 
tassa, is prepared by digesting potassa with pure ferro-cyanate of 
the peroxide of iron (prussian blue,) which last parts with its 
acid, and thereby neutralizes the potassa. It is also formed in 
the manufacture of prussian blue, when the blood, in hoofs and 
horns of animals are calcined with potassa and iron. It appears 
in the forms of large, transparent, lemon colored crystals. The 
crystalized salts consist of cyan. 3 equiv. potassium 2 equiv. iron 
1 equiv. Hyd., 3 equiv. Ox., 3 equivalents. 

740. Hydro-Jerro-cyanate of the peroxide of iron. This salt 
is the basis of the well known color— prussian blue. It is form¬ 
ed by mixing the hydro-ferro of potassa, with the peroxide of 
iron ; the precipitate is of deep blue color. In the prussian blue 
of commerce this salt is mixed with alumine and the peroxide 
of iron. It is prepared by heating animal substances, with po¬ 
tassa and a salt of iron in a large iron crucible. Carbon and ni¬ 
trogen arising from the decomposition of the animal matter form 
cyanogen, which uniting with disengaged hydrogen and a por¬ 
tion of iron, forms hydro-ferro-cyanic acid . The acid now com¬ 
bining with iron and potassa forms a salt with a double base, 
which may be called a hydro-ferro-cyanate of iron and potassa. 

741. We have now completed an outline of inorganic Chem¬ 
istry. In a subject embracing such a vast variety of combina¬ 
tions, and susceptible of so much amplification, we have found 
it difficult to keep within the boundary of a simple elementary 
course of instruction. Yet conscious that a few principles well 
understood are of more advantage to the student, than a mass of 

738. Characteristics of the Hydro-ferro-cyanates. 

739. Hydro-ferro-cyanate of potassa 

740. Hydro-ferro-cyanate of the peroxide of iron. Prussian blue. 

741. Remarks in concluding the department of Inorganic Chemistry. 




PRUSSIAN BLUE. 


325 


unconnected facts, we have endeavored to render prominent the 
general laws of chemical science, and our choice of facts has 
often been directed by this view rather than by their individual 
importance. For the same reason we have been more careful to 
explain the rationale of the changes described, than to enter into 
minute details of manipulations.* We have not attempted to 
follow the elementary substances through all their metamorpho¬ 
ses in the various arts and manufactures, but have sought exam¬ 
ples from the most common and familiar facts to illustrate prin¬ 
ciples, and on the other hand have endeavored to explain similar 
facts by a recurrence to principles previouly established. 

* For a knowledge of these the student is referred to the author’s 
Dictionary of Chemistry, Farraday’s “ Chemical Manipulations,” Gray’s 
“ Operative Chemist,” Silliman’s Elements, Hare’s Compendium, The- 
nard’s Traite de Chemie, &c. 

28 * 


PART III. 

' / . . / ■ 

ORGANIC CHEMISTRY. 


LECTURE XXXI. 

CONSIDERATIONS ON THE SUBJECT OF ORGANIC CHEMISTRY.- 

VEGETABLE CHEMISTRY. -PROXIMATE PRINCIPLES AND ULTI¬ 
MATE ELEMENTS.-VEGETABLE ACIDS. 

742. The subject on which we are now to enter is Organic 
Chemistry , by which we mean the study of animal and vegetable 
substances , with the elements which enter into their composition, 
and the modes of combination and arrangement of these ele¬ 
ments. Though organic substances differ greatly from inorgan¬ 
ic, we have here no new elements presented ; but the vital power 
produces, in plants and animals, changes unlike any of the effects 
of mere mechanical action. Inorganic substances generally pos¬ 
sess some peculiar principle, which distinguishes one from 
another ; as in the following acids, nitric, sulphuric, phosphoric, 
&c., where one contains nitrogen, another sulphur, another phos¬ 
phorus, &c. But organic products, with few exceptions are 
composed of the same elementary principles, varying in their 
proportions. They are mostly composed of carbon, oxygen, and 
hydrogen ; nitrogen is less abundant in plants than in animals. 
Lime, potassa, iron, phosphorus, and some other substances 
usually exist in organic matter, though but in small proportions. 

743. It is beyond the power of science to explain in what 
manner the living principle operates in plants and animals, pro¬ 
ducing in the former secretions of sap, gum, resin, oil, &c., and 
in the latter secretions of a very different nature, as blood, bile, 
&c. Neither is the chemist able, in organic chemistry to prove 
the results of his analysis by synthesis. Although analysis 

742. What is Organic Chemistry ? Cause of the difference between 
organic and inorganic substances. 

743. Effects of the living principle. Organic compounds cannot be 
recomposed. Transmutation of matter exhibited in organic substances. 




ORGANIC PRODUCTS. 


327 


enables him to ascertain the simple elements which exist in gum 
or sugar, he cannot, by the union of hydrogen, oxygen and car¬ 
bon in the same proportions in which they constitute these 
apparently simple compounds, form similar ones ; but water and 
carbonic acid only result from his combination. If the simplest 
products of vegetable organization cannot be imitated by man, 
much less can he create any action which bears the remotest 
analogy to that of the mysterious principle of life. Every plant 
and animal may be considered a laboratory in which a presiding 
genius is carrying on processes of transmutation wholly unin¬ 
telligible to those who behold their results ; out of the dust of 
the earth springs a beautiful plant, which drinking in the most 
offensive vapors, exhales the sweetest fragrance, and glowing 
with bright, or delicate tints forms a strong contrast with the 
dark unsightly soil which gave it birth. The same elements 
moreover go to form the calyx, petals and pollen of the flower, 
with its stem, leaves and roots. Where is the chemist who can 
explain the cause of the various colors, texture, and odor of 
these different organs, all resulting from the same elements, plac¬ 
ed in the same circumstances of air, moisture, light and heat ? 

In the young infant, how rapidly does milk become changed 
into fleshy fibres, and cellular membranes, giving roundness and 
beauty of outline to the limbs, while at the same time it is adding 
hardness to the incipient bones, and firmness to the unstrung 
muscles ! 

744. u Animal and vegetable substances are all decomposed by 
a red heat, and most of these at a temperature much below this. 
When heated in the open air, or with substances which yield 
oxygen freely, they burn, and are converted into water and car¬ 
bonic acid ; but if exposed to heat in vessels from which atmos¬ 
pheric air is excluded, very complicated products ensue. A 
compound consisting only of carbon, hydrogen, and oxygen, 
yields water, carbonic acid, carbonic oxide, carburetted hydrogen 
of various kinds, and probably pure hydrogen. Besides these 
products, some acetic acid is commonly generated, together with 
a volatile oil which has a dark color and burnt odor, and is hence 
called empyreumatic oil . A substance containing nitrogen only in 
addition to carbon, oxygen and hydrogen, yields ammonia, cy¬ 
anogen, and probably free nitrogen. 

745. Organic products are distinguished by the following 
characteristics : 

1. Composed of the same elements. 

2. Readily undergo spontaneous decomposition. 


744. Decomposition of animal and vegetable substances. 

745. Characteristics of organic products. 



328 


ORGANIC CHEMISTRY. 


3. Cannot be formed by a direct union of these principles, and 

4. Are all decomposed at a red heat.”* 

746. Every distinct compound which exists ready formed in 
organic bodies is called a proximate or immediate principle , in dis¬ 
tinction from the ultimate elements which remain when these 
principles are reduced to their simplest parts. Thus gum and 
turpentine are among the proximate principles of plants, gelatin 
and albumen among those of animals. Carbon, oxygen, &c. are 
the ultimate elements . 


VEGETABLE CHEMISTRY. 

747. The proximate principles of plants are sometimes con¬ 
fined to a particular part, sometimes distributed over the whole, 
thus pollenin is found only in the pollen of flowers, while sugar 
exists in the juices diffused throughout the whole body of many 
plants. There are various methods of procuring these proximate 
principles. The sap of the sugar maple, cane and beet yield sugar 
being concentrated and evaporated by boiling. Starch is made 
by mechanical division of the potatoe, corn, and some other 
leguminous plants, and then washing the particles in which it 
exists in pure water. On letting' the water stand, the starch sub¬ 
sides. Volatile Oils are obtained by distillation. More than 
forty vegetable proximate principles have been discovered < 

748. There are still many difficulties in the way of an accurate analy¬ 
sis of vegetable principles, though this subject has within a few years re¬ 
ceived much attention. The observations of Gay-Lussac and Thenard, 
led them to form the following general conclusions with respect to the 
constitution of vegetable substances. 1. A vegetable substance is al¬ 
ways acid, when the oxygen in relation to hydrogen is in greater pro¬ 
portion than to form water, or in other words when oxygen is in excess. 

2. When hydrogen is in excess, or when the oxygen is in relation to 
it, in a less proportion than is necessary to form water, the body is resin¬ 
ous, oily, or alcoholic. 

3. When the oxygen and hydrogen are in the proportions to form wa¬ 
ter, or neither in excess, the body is neither acid, resinous, oily, &e., but 
sacharine, as sugar; mucilaginous, as gum, &c. 

749. In conformity with these views of the French Chemists, a classi¬ 
fication of proximate principles has been made by Turner. “ These 
laws,” he remarks, “ are not rigidly exact, nor do they include the 

* Turner. 


746. Distinction between proximate principles and ultimate elements. 

747. Situation of the proximate principles of plants. Number of 
vegetable proximate principles. 

748. Conclusions of Gay-Lussac and Thenard respecting the con¬ 
stitution of vegetable substances. 

749. Turner’s classification of proximate principles. 



VEGETABLE ACIDS. 


329 


vegetable products containing nitrogen, but for want of a better princi¬ 
ple of classification I shall follow M. Thenard in making them to a cer¬ 
tain extent the basis of my arrangement.” 

Division of proximate principles. 

1. Vegetable acids. 

2. Vegetable alkalies. 

3. Oils, resins, alcohol; substances with an excess of hydrogen. 

4. Sugar, starch, gum, &c., when hydrogen and oxygen are in 
proportions to form water. 

5. Compounds which are not known to belong to the other 
divisions, as coloring matter, tannin, &c. 

VEGETABLE ACIDS. 

750. The vegetable acids are composed of oxygen, hydrogen, 
and carbon ; they redden blue vegetable colors, have mostly a 
sharp taste, and neutralize salifiable bases, forming salts. 

Thenard enumerates 34 vegetable acids. But few of them are much 
known. The names of these acids are generally derived from the vege¬ 
tables in which they exist in the greatest quantity. These acids are de¬ 
composed by heat, or by hot nitric acid. The products of their decompo¬ 
sition are carbonic acid and water. In considering the acids, we shall 
notice the salts formed by them with salifiable bases. 

751. Acetic Acid. Of all the vegetable acids this is the most 
extensively used. It exists ready formed in the fruit of the 
Rhustyphinus (sumach,) Sambucus nigra (elder,) and the sap 
of many plants either free, or combined with lime, or potassa. 
It is one of the principal products of the acid fermentation. It is 
this which gives to -vinegar its sourness. Besides acetic acid, 
vinegar contains more or less water, mucilaginous matter, alco¬ 
hol, and various salts in solution. 

In France, vinegar is made by exposing wine to the acid fermentation. 
In England, malt liquors are used for this purpose ; and in the United 
States, most of the vinegar is made from cider. It is very easy for every 
family to make their own vinegar, and much better economy than to buy; 
as cider is far less expensive than vinegar, and there is little trouble and 
expense in the manufacture. The barrel with the cider should be placed 
where the sun and air may have access to it, and be furnished with some 
of the mother of Vinegar, a mucilaginous, whitish ropy substance which 
is usually found at the bottom of strong vinegar. This substance seems 
equally necessary in hastening the acetous fermentation of cider, as yeast 
is in promoting the vinous fermentation of bread. Molasses spread upon 
a sheet of paper or a lump of raised dough thrown into the barrel, assists 


750. General characteristics of vegetable acids. Number. Derivation 
of the name of these acids. Decomposition, &c. 

751. Acetic acid. Vinegar. Mother of Vinegar. Wine Vinegar. 
Distillation of Vinegar. ‘Freezing of Vinegar. 



330 


ORGANIC CHEMISTRY, 


in the change of cider to vinegar. After the vinegar is formed, more 
cider is added from time to time, and thus the barrel may be kept re¬ 
plenished, and furnish vinegar for all domestic uses. The vinegar from 
wine contains a certain portion of the bi-tartrate of potassa which may be 
obtained by evaporation. Vinegar is obtained pure by distillation, it is 
then acetic acid distilled with water, and was formerly called acetous 
acid, on the supposition that it was a distinct acid. When vinegar is ex¬ 
posed to severe cold, some of its water freezes, and it becomes stronger, 
or more like pure acetic acid. 

752. Acetic acid is also obtained by purifying the pyroligneous 
or empyreumatic acid, which is procured from the carbonization 
of wood in close vessels. On being distilled a brown transparent 
liquid is obtained having a strong smell of smoke. This pyro¬ 
ligneous acid is beneficial in the preservation of meat, to which 
it imparts a flavor like that obtained in the common process of 
smoking. 

753. Pure acetic acid is obtained from the bin-acetate of copper, (crys¬ 
tallized verdigris,) and from the acetates of potassa and soda. The ace¬ 
tate is distilled with sulphuric acid, which, uniting with the base, disen¬ 
gages acetic acid. 

Acetic acid is very volatile ; has a sour taste and other acid 
properties; its odor is refreshing, and hence vinegar is often 
burnt in sick rooms. Its crystals contain one equivalent of acid 
with one of water. The strongest acid is a hydrate ; it cannot 
be obtained without a portion of water. Acetic acid consists of 
4 equivalents of carbon ; 3 of oxygen and 2 of hydrogen. 

754. Acetic acid acts readily on ammonia and most of the 
metallic oxides, forming salts called acetates . 

Acetate of ammonia is used in medicine under the name of spirit of 
minderus ; it is obtained by saturating carbonate of ammonia with acetic 
acid. The acetates of soda and potassa are employed for obtaining acetic 
acid. They may be prepared by neutralizing potassa and soda with dis¬ 
tilled vinegar. The acetate of potassa exists in the sap of many plants. 
The acetate of alumina is used by dyers and calico printers; that of 
baryta as a reagent in Chemistry. 

Acetate of Copper furnishes the green paint known as Verde- 
gris; this may be obtained by exposing metallic copper to the 
vapour of vinegar ; the metal first oxidizes by the action of the 
oxygen of the air, and the oxide then unites with the acid. There 
are several definite compounds of copper and acetic acid. 

Acetate of lead is made by distilling the carbonate of lead or 
litharge in distilled vinegar. It has a sweetish taste, and is 
known as sugar of lead . It is much used in medicine, and in the 
arts. 


752. Pyroligneous acid. 

753. Acetic acid obtained by the distillation of acetates. Properties of 
acetic acid. Its constituent elements. 

754. Acetates. Acetate of copper. Acetate of lead. 



OXALIC ACID. 


331 


OXALIC ACID. 

755. So named from the oxalis acetosella , the wood-sorrel; it 
was discovered by Scheele in that plant where it is combined 
with potassa, forming the salt called oxalate of potassa. 

Oxalic acid may be obtained by heating nitric acid in a retort with su¬ 
gar, starch, alcohol or most vegetable acids. These substances are not 
immediately changed into oxalic acid ; malic and acetic acids are usually 
the first products, they are transformed into oxalic acid by adding a new 
portion of nitric acid. At first very large crystals are obtained ; but as 
the crystalization is successively repeated, they are deprived of the nitric 
acid which they contain, and appear under the form of small delicate 
prisms. 

This acid is much used to remove colors occasioned by the 
oxides or salts of iron. The strong sour taste of this acid is ap¬ 
parent in the different species of sorrel; the bruised green leaves 
of these plants, on account of the presence of this acid, are effica¬ 
cious in removing stains, and iron rust from linen. In combina¬ 
tion with lime, oxalic acid exists in the leaves of the garden 
rhubarb. It acts as a poison on the animal system. 

Its crystals contain 4 equivalents of water (9X4=36) with one equiva¬ 
lent of acid 36, their equivalent number is therefore 72. “ It is singular,” 
says Silliman, “ that this powerful acid in firm crystals should be mid¬ 
way between the two gases carbonic acid and carbonic oxide, and it may 
ever be regarded as composed of 1 equivalent of carbonic acid, 22, and 
one of carbonic oxide, 14=36. It has the composition of a mineral acid, 
and it has been proposed to call it the carbonous acid which its compo¬ 
sition would fully justify.” 

The combination of oxalic acid with salifiable bases forms 
salts called oxalates and sold under the name of salts of sorrel 
and salts of lemon ; the latter name however belongs to the 
nitrates, which we have yet to notice. 

The bin-oxalate of potassa, called salt of sorrel is used to re¬ 
move stains of iron and ink. One equivalent of the acid gives 
to the iron forming a soluble oxalate of iron, and leaving a solu¬ 
ble oxalate of potassa. This oxalate is used as a test for lime, 
with which it forms an insoluble precipitate. This is more 
soluble than the bin-oxalate, a circumstance which is not ac¬ 
cording to the general analogy of salts. 

The quadroxolate of potassa is obtained by digesting the bin- 
oxolate with nitric acid, which, uniting with half the base, leaves 
the other half combined with the whole of the oxalic acid, of 
which there are now four proportions with one of potassa. If, 

755. Name, discovery, &c. of Oxalic acid. Method of obtaining it. 
Crystals. Uses of Oxalic acid, &c. Composition of its crystals. Oxa¬ 
lates. Binoxalate of potassa. Quadroxalate of potassa. Composition of 
the oxalates of potassa. 



332 


ORGANIC CHEMISTRY. 


of 4 parts of this salt, 3 are decomposed, the disengaged potassa 
can be exactly saturated with the acid which may be obtained 
by the decomposition of the 1 remaining part. 

The nature of the oxalates of potassa beautifully illustrates the 
law of multiple proportions. Their composition is as follows. 

Equiv. Equiv. Base. Acid. Equiv. 
of base, of acid. 

Oxalate contains 1 add 1 = 48 add 36 = 84. 

Bm-oxalates “ 1 add 2 == 48 add 72 = 120. 

Quadroxalates “ 1 add 4 = 48 add 144 = 192. 

TARTARIC ACID. 

756. This was first obtained from cream of tartar (the tartar 
procured from wine) from whence it received its name. It exists 
in the tamarind, pine apple and many other acidulous fruits, in 
balm, sage, and probably sumach. 

It is obtained by decomposing cream of tartar (the bi-tartrate of potassa) 
by carbonate of lime. Carbonic acid goes off with effervescence, and one 
equivalent, a test of the insoluble tartrate of lime is precipitated, while 
one equivalent of the neutral tartrate remains in solution. The precipi¬ 
tate is washed and then mixed with water containing some sulphuric acid; 
the latter by uniting with the base of the tartrate, disengages tartaric 
acid, which when filtered and evaporated is obtained in prismatic crys¬ 
tals, soluble in water, and possessing strong acid properties. 

Tartaric acid is very sour, it is used in fevers as a cooling 
drink, and sometimes as an agreeable beverage in warm weather ; 
with soda it forms an effervescing mixture, the tartrate of soda. 

When heated in close vessels the liquid product of destructive distilla¬ 
tion yields an acid called pyro-tartaric, but supposed by some to be acetic 
acid mixed with oily matter. Tartaric acid is capable of disengaging 
potassa from all other acids ; when mixed with any of the salts of potassa 
it decomposes them, forming white precipitate, the bitartrate of potassa. 
This acid is remarkable for its tendency to form double salts among which 
are the tartrate of antimony and potassa , or the tartar emetic of medicine ; 
and the tartrate of potassa and soda , or Rochelle salt. 

757. Bi-tartrate of potassa, cream of tartar exists in the juice of 
the grape, and is found lining the sides and bottom of wine casks, 
owing to the insolubility of this salt in alcohol, it is gradually de¬ 
posited during the vinous fermentation of the red wines, espe¬ 
cially. It is often sold in a crude state, when it is called wine 
stone. This crude tartar has the color of the wine. It is purified 
by dissolving, filtering, and crystalizing. White crystals are skim¬ 
med off the surface of the solution ; these are called cream of tar - 

756. Tartaric acid, derivation of its name, plants in which it exists, &c. 
Crystals of tartaric acid. Properties. Pyro-tartaric acid. Strong affin¬ 
ity of tartaric acid for potassa. 

757. Bi-tartrate of potassa. 




CITRIC ACID. 


333 


tar. Its peculiar sour taste is well known, and it has other acid 
properties. It is composed of two equivalents of acid and one of 
base. This salt is valuable in medicine. 

758. Tartrate of potassa or soluble tartar , containing one equiv¬ 
alent of acid with one of the base, is obtained by saturating with 
potassa, the excess of acid of the cream of tartar. It was former¬ 
ly used in medicine, under the name of vegetable salt. 

759. Citric acid is named from the genus of plants Citrus con¬ 
taining the orange and lemon. 

It may be obtained by pouring lemon juice upon chalk, and decompos¬ 
ing the citrate of lime thus formed, by sulphuric acid. The sulphate of 
lime being insoluble, is separated from the liquid citric acid by filtering. 
Large transparent crystals are obtained by evaporating the liquid. 

This acid is used as a substitute for lemon juice, and for effer¬ 
vescing draughts with the carbonates of soda; the effervescence 
is caused by the escape of carbonic acid gas, and the liquid is 
then a solution of citrate of soda. Spots caused by iron and ink 
are removed by citric acid. Its crystals are remarkable for not be¬ 
ing affected by the air. When heated,they suffer the watery fusion, 
the acid decomposes and a peculiar compound called hydro-citric 
acid sublimes. Scheele first ascertained that the sourness of the 
lemon and lime were owing to the presence of the peculiar acid, 
now called the citric. This is often combined with malic acid in 
red fruits. The only citrate known to exist in nature is that of 
lime, which is found in very small quantities in fruits containing 
citric acid. 

760. Malic acid is contained in the apple ( Pyrus malus ) its 
name being derived from malus , the specific name of the plant. 
This acid exists also in the juices of the cherry, currant, goose¬ 
berry, strawberry, barberry, house-leek, berries of the mountain 
ash, &c. It may also be obtained by digesting sugar with three 
times its weight of nitric acid. 

The salts of malic acid are called malates. When sheet lead 
is steeped in apple juice, malate of lead is formed. The malates 
are usually distinguished from the citrates in being more solu¬ 
ble. Malic acid combined with citric and tartaric acids, together 
with sugar, mucilage and some other principles, give their flavor 
to fruits, and according as one or the other acids, or sugar pre¬ 
vails, is the specific flavor which characterizes them. In the 
lemon, citric acid is greatly in excess ; in the orange, it is gene¬ 
rally neutralized by sugar. In sour apples, malic acid is in excess; 
in the whortleberry and strawberry malic and citric acids exist 


758. Tartrate of potassa. 

759. Citric acid, its name, made of obtaining, &c. Uses. Effect of heat 
upon crystals of citric acid, &c. Citrate of lime. 

760. Malic acid. Malates. Cause of the specific flavor of fruits. 

29 



334 


ORGANIC CHEMISTRY. 


in nearly equal quantities, with a large proportion of sugar. In 
the grape the tartaric acid is in excess. As fruits ripen, they 
usually contain a larger proportion of sugar. 

761. Benzoic acid is obtained from the gum of the Styrax benzoe , 
plant of the East Indies. It is also found in castor, cinnamon, 
in some volatile oils, in the flowers of the Trifolium melilotus, 
and other vegetables as well as some animal substances. 

It is usually obtained by boiling gum benzoic with a solu¬ 
tion of carbonate of potassa; a benzoate of potassa is formed, which, 
by the addition of muriatic acid, forms muriate of potassa and disengages 
benzoic acid. The taste of this acid is rather sweetish ; but it is decidedly 
acid in its effect on vegetable colors, and with alkalies. Its crystals are 
white with a silky lusture, the odor is aromatic and pleasant. It gives to 
the paregoric elixir its peculiar odor and taste. 

Benzoic acid burns with a yellow flame when exposed to 
strong heat; at common temperature, it suffers no change from 
the air, and even assists the action of nitric acid. Its salts are 
called benzoates . 

762. Gallic acid was first discovered by Scheele, in 1786, in 
gall-nuts, or the excrescences found upon the leaves of a species 
of oak, supposed to be occasioned by the puncture of an insect 
whose egg is often found in the center of the nut. The nuts are 
about the size of a pigeon’s egg, of a brown color and uneven sur¬ 
face. They are knOwn in commerce as nut-galls, and are used 
in domestic coloring to produce slate color and black. 

Gallic acid, at first supposed to be peculiar to the gall nut, is 
now known to be associated with tannin in the barks of most 
trees, and in astringent vegetables. 

There are various methods of obtaining gallic acid. Scheele made an 
infusion of powdered gall-nuts in four times their weight of water ; after 
standing a few days, the infusion was strained or filtered, and then kept 
for two months in a warm atmosphere. The surface of the liquid becomes 
mouldy, the tannin (which is always combined with gallic acid) decom¬ 
posed, and a yellowish cry staline matter was deposited. This is an impure 
gallic acid, containing some coloring matter, and a peculiar acid called 
ellagic acid ; as the latter is insoluble in boiling water,, the gallic acid 
was separated from it by boiling, and divested of the coloring matter by 
digesting with a proportion of animal charcoal, (ivory black.) It forms 
white silky crystals possessing the properties of a weak acid, with an 
astringent taste. With lime water it gives a brownish green precipitate, 
which, when undissolved by an excess of solution, acquires a redish hue. 


761. Plants which contain benzoic acid. How is this acid obtained ? 
Taste, &c. Benzoates. 

762. Discovery of Gallic acid. Gall nuts. Substances containing 
gallic acid. Scheeles’ method of obtaining this acid. Crystals and prop¬ 
erties of gallic acid. Ink. Cause of the stains made by tea on knives, 
&c. Distinction between gallic acid and tannin. Gallates. 



GALLIC ACID. 


335 


Gallic acid is an important test with the metals. It precipi¬ 
tates iron deep black, and with tannin forms the basis of ink and 
black dyes. It is a mixture of the gallate and tannate of iron, 
and it is soluble in the acid which is always present in this fluid; 
thus, when ink becomes thick, we dissolve it by adding weak 
vinegar. The black stains caused by tea on knives and other 
iron or steel utensils, are owing to gallic acid and tannin, acting 
on iron. Gallic acid is distinguished from tannin by giving no 
precipitate in a solution of gelatine. The salts of this acid are 
called gdilates. The per-g dilate of iron is blue, the gallates of 
potassa and soda are colorless. 

763. Ellagic (ellagique) acid was so named by the French Chemist 
Beaconnot, by an invasion of the word galle (gall.) Thenard suppo¬ 
ses that it forms salts with the alkalies, which he terms ellagates ; he con¬ 
siders that there is a neutral ellagate of potassa, which is soluble and 
greens vegetable blues; and an acid ellagate which is white and insolu¬ 
ble. He suggests that the ellagic acid does not exist in the gall-nut, but 
is formed during the preparation of gallic acid when tannin decompo¬ 
ses by contact with the air. 

764. We have now described the most important of the vegetable acids; 
many of which are indispensable in manufactures and the arts. There 
are others which are less known : among them are : Mucic or saccholac- 
lic acid (so called from mucus , gum) which was obtained by Scheele by 
the action of nitric acid on gum, sugar or milk,* &c. The precipitate is 
in the form of a white, gritty powder, with feeble acid properties. When 
decomposed by heat, it yields, besides the usual vegetable products, a 
white sublimate called pyro-macic-acid. The saccholactates have been 
little studied. This acid belongs both to animal and vegetable com¬ 
pounds. 

765. Pectic acid derives its name from the Greek pedis, coagulum, be¬ 
ing remarkable for its tendency to coagulate or to exist in a gelatinous 
form. It was first obtained by Beaconnot from the pulp of carrots, boil¬ 
ed with potassa; the alkali unites with the pectic acid and forms a gela- 

inous mass which is the pedate of potassa. On adding an acid, the pec- 
tate decomposes, giving up its base to the new acid, and disengaging 
pectic acid in the form of jelly which is insoluble in cold water. 

766. Indigotic and carbazotic acids are obtained by the action of ni¬ 
tric acid on indigo. When indigo is boiled in diluted nitric acid, car¬ 
bonic, prussic and nitrous acids are evolved, and in the liquid, besides 
carbazotic acid, resinous matter, &c. a peculiar acid is found called by 
Chevreul the acid of indigo. 

The carbazotic acid appearsln yellow crystaline scales, and is readily 

* The word saccholactic is derived from saccliarum sugar, and lade 
milk. 


763. Origin of the name ellagic acid. Ellagates. Thenard’s opin¬ 
ion of the production of ellagic acid. 

764. Mucic or Saccholactic acid. 

765. Pectic acid. 

766. Mode of obtaining indigotic and carbazotic acids. Properties of 
these acids. Change of the indigotic to the carbazotic acid. Composi¬ 
tion of the two acids. Derivation of the name carbazotic. 



336 


INORGANIC CHEMISTRY. 


dissolved by ether and alcohol. It acts like a strong acid upon metallic 
oxides, forming salts called carbazotates. The indigotic acid changes to 
carbazotic by the action of strong nitric acid, disengaging carbonic acid 
and nitrous acid fumes, and producing a small portion of oxalic acid. The 
change appears to depend on the loss of both carbon and oxygen ; the 
composition of the two acids appear to be as follows : 


Carbazotic acid. 


Indigotic acid. 
Carbon 15 equiv. 


30 equiv. 
10 “ 

4 “ 


Oxygen 10 “ 

Nitrogen 2 “ 


The name carbazotic is derived from carbon and azote, the latter being 
the name by which French chemists usually designate nitrogen. 

767. Succinic acid is named from succinum , amber, from which it is ob¬ 
tained It was formerly called salt of amber. When powdered amber 
is heated in a retort, the acid sublimes, and is Condensed in the receiver. 
It crystalizes into anhydrous prisms. Its salts are called succinates. 

Camphoric acid is the product Of the' action of 14 parts nitric • acid, 
with t of camphor, at the temperature of 77° F. Its salts are called 
camphor ates. 

768. Moric or moroxylic acid is found combined with lime in the morus 
alba or white mulberry. Kinic acid exists in combination with lime in 
the cinchona (Peruvian bark.) Meconic acid is combined with morphine 
in opium. Zumic acid, from Zume, yeast, was discovered by Beaconnot 
in vegetable substances which have passed through the acetous fermen¬ 
tation ; from more recent observation it appears not to be essentially' dif¬ 
ferent from,acetic acid. 

Hydro-cyanic or prussic acid, exists in many plants, as bitter almond, 
peach leaves and blossoms, &c. 

Rheumic acid was formerly supposed to exist as a distinct acid in the 
garden rhubarb (Rheum). It is now considered as identical with the ox¬ 
alic acid. Bolctic acid is a peculiar substance discovered by Beaconnot 
in mushrooms called familiarly touchwood ,—in Botany Boletus igniariils. 
Suberic acid is procured from the cork plant (Quercus suber.) 

We might extend our list of vegetable acids; but it is highly proba¬ 
ble that future discoveries may greatly reduce their number, by showing 
many of those which are now considered different to be the same, modi¬ 
fied by peculiar circumstances ; on the other hand, it is very possible that 
acids may be discovered whose existence is now unknown. 


767 Succinic acid. Camphoric acid. 

768. Moric acid. Kinic acid. Meconic acid. Zumic acid. Hy¬ 
dro-cyanic or prussic acid. Rheumic acid. Boletic acid. Number and 
distinctive characters of vegetable acids not entirely settled. 



VEGETABLE ALKALIES. 


337 


LECTURE XXXII. 

VEGETABLE ALKALIES, OILS, RESINS, &C. 

769. By the name vegetable salifiable bases or alkalies is de¬ 
signated those proximate principles which exist in certain vege¬ 
table substances, which united with acids, saturating them in a 
greater or less degree, and forming with them combinations, 
which may properly be called salts. 

The discovery of these vegetable bases was made by M. Ser- 
tuerner, in 1805, in some experiments upon opium. But his 
publication of the discovery, attracted little attention, until some 
new communications of the author awakened chemists to the 
nature and importance of the subject. Such researches have al¬ 
ready been made by others, as easily led to the conviction that 
the property possessed by many vegetable substances of acting 
powerfully on the animal economy, was owing to the presence 
of peculiar salifiable bases ; and that to obtain these active prin¬ 
ciples separate from a mass of useless, or mere counteracting 
matter, must be an important desideratum in medicine. 

770. For example ; the Peruvian bark, cinchona , had long been in high 
repute for its medicinal powers; but it was evident that, combined with 
the energetic principle of the bark, were others, such for instance as tan¬ 
nin and woody fibre, which could not aid in producing the desired specif¬ 
ic effect, and that to crowd the weak stomach with useless or hurtful 
substances in order to introduce a medicinal one, was contrary to the dic¬ 
tates of common sense as well as the principles of science. With this 
important and definite object in view, two French chemists, Pelletier 
and Caventou, commenced a series of experiments with cinchona, which 
resulted in the discovery of its active medicinal principle. This they 
called quinine. A small quantity of this concentrated alkali produces 
powerful effects on the human system, particularly in intermitting fevers, 
and other diseases. 

771. The vegetable alkalies are not found free in nature, but 
exist in plants combined with acids forming natural salts, more 
or less soluble in water. In order to obtain the alkaline princi¬ 
ple, the vegetable substance is digested in water, and the salt 
being thus dissolved, some powerful salifiable base, as ammonia 

769. Description of vegetable alkalies. Their discovery by Sertuer- 
ner. Chemists awakened to the importance of the discovery. 

870. Combination of the medicinal principle of the Peruvian bark, 
with useless or hurtful matter. Discovery of quinine. 

771. Method of obtaining the alkaline principle of plants. Properties 
of vegetable alkalies. 

29 * 



338 


ORGANIC CHEMISTRY. 


or potassa is added. This uniting with the acid, leaves the al¬ 
kali free, the latter being insoluble in water may be obtained by 
precipitation. 

Vegetable alkalies are soluble in hot alcohol, and crystallize on 
cooling. They are solid, bitter or acid, inodorous, change blue 
vegetable colors green, and are heavier than water. When de¬ 
composed by fire, they yield ammonia ; this is formed by the 
carbon and nitrogen,* which, with hydrogen and oxygen, con¬ 
stitute their ultimate elements. They form combinations with 
sulphur. They dissolve in chlorine and iodine. Their capaci¬ 
ty of saturation is feeble, therefore their equivalent combining 
proportions are great; that of morphine for example, is stated at 
325. When salts with vegetable bases are decomposed by the 
voltaic pile, the alkali appears at the negative, and the acid at the 
positive pole. 


SUBSTANCES OBTAINED FROM OPIUM. 

772. Morphia or morphine (so called from Morpheus known in heathen 
mythology as the God of Sleep) is the narcotic principle of opium, in 
which it exists combined with Meconic acid. Opium is the dried juice 
of the poppy ; and besides meconic acid , contains various principles, as 
narcotine , gum, resin, lignia, oil, and caoutchouc or gum elastic. Mor¬ 
phia in most cases, acts on the animal system as a violent poison ; but 
did it meet with no acids in the stomach, it would be inert on account of 
its insoluble nature; thus experiments have given different results, as 
the stomach of the animals into which it has been introduced have con¬ 
tained more or less acid. 

When morphia has been taken in too large quantity, a solution of am¬ 
monia may decompose the soluble salt, formed by it with the acetic and 
other acids in the stomach, and the vegetable alkali will thus be precipi¬ 
tated in an insoluble state. Ammonia and other alkalies are recommend¬ 
ed in cases where laudanum or any preparation of opium is taken in ex¬ 
cess ; they decompose the meconate of morphia, which is the active prin¬ 
ciple and produce an insoluble precipitate of morphia. Infusions of cof¬ 
fee and nut-galls counteract the effects of morphia, by forming with it 
insoluble compounds. 

When properly used, morphia is a highly valuable medicine ; it is 
said to “ produce the soothing effects of opium, without causing the fe¬ 
verish excitement, heat, and headache which so often accompanies the 
use of that drug.” The acetate of morphia is very soluble, and the 
most active of the salts of this alkali. 

* Nitrogen was formerly considered as a distinctive character of an¬ 
imal matter; it is now known to exist in many vegetable compounds, 
though more sparingly than in animal. 


772. Morphia, with what acid combined. Various principles of opi¬ 
um. Antidotes to the poison of morphia, or other preparations of opium. 
Uses of morphia. Acetate of morphia. 



NARCOTINE. 


339 


773. Meconic acid , so called from the Greek mekon , poppy,’ is sour 
and bitter, and reddens vegetable colors; it gives a red tint to the per- 
salts of iron, and an emerald green to sulphate of copper. It seems in¬ 
active with respect to the animal system. The meconate of morphia, 
therefore, must owe its energetic action to the increased solubility of 
morphine in the state of a salt. 

774. Narcotine is an independent principle which, though not alkaline 
we shall here notice on account of its association with meconic acid and 
morphia. It is prepared by digesting an evaporated infusion of 
opium in sulphuric ether. The ether does not act on the meconate of 
morphia, but absorbs the narcotine, which may be crystalized by evapora¬ 
tion. The powerful effects of opium have been attributed to narcotine. 
As acids mitigate its power, this appears to explain the use of vinegar in 
counteracting some of the effects of opium, and also the comparative mild¬ 
ness of the black drop , in which the narcotine is in solution in vinegar, 
nitric or tartaric acid.” 

Substances obtained from cinchona or Peruvian bark , Cinchonia 

and Quinta. 

775. The Cinchona or Peruvian bark of commerce is of three kinds, 
the .pale bark which is obtained from the cinchona condaminea, the yel¬ 
low bark of the C. cordifolia ., and the red bark of the C. obeongifolia. 
The medicinal property of the bark is found to reside in two alkalies, 
the cinchonia or cinchonine and the quinia or quinine; the former exists 
in the.pale bark, while both are contained in the red bark. These two 
vegetable alkalies are found to bear to each other much the same rela¬ 
tion as potassa and soda relatively sustain ; they both exist in combina¬ 
tion with an acid called Zcim'cacid, which bears to them the same relation 
as the meconic acid bears to morphia. 

According to the analysis of Pelletier and Dumas the following is the 
composition of these two alkalies, 


Cinchonine. 

Carbon 

76.97 

Quinine. 

75.02 

Oxygen 

7.79 

10.43 

Hydrogen 

6.22 

6.66 

Nitrogen 

9.02 

8.45 


100.00 

100.56 


The methods for obtaining cinchonine and quinine are much the same 
as for morphia. The febrifuge virtues of quinine are superior to those of 
cinchonine. The former is mostly used in the form of a sulphate con¬ 
sisting of 90 parts of alkali and 10 of the acid. 

776. We will now consider the other vegetable alkalies of any impor- 


773. Meconic acid. 

774. Narcotine. 

775. Different kinds of Cinchona. Medicinal properties of the bark 
reside in two alkalies. Relation which cinchonine and quinine bear to 
each other. Composition of Cinchonine and Quinine. Methods of ob¬ 
taining these principles. Their comparative value in medicine, &c. 

776. Strychnia. Brucia. Sanguinaria. Veratria. Emetia. 







340 


ORGANIC CHEMISTRY. 


tance. Strychnia is obtained from the Strychnos nux vomica :, and Ignatia 
or St. Ignatius. It is the poisonous principle of a very noxious plant. It 
exists in the Upas tree of Java. 

Brucia was discovered in the Brucia antidysenierica ; it has since been 
found in the plants which yield Strychnia, and resembles that alkali in 
its poisonous properties, but is less active. 

Sanguinaria has been discovered in the sanguinaria canadensis or blood 
root. The medicinal virtues of the blood root are said to exist in this 
alkaline principle. 

Veratria is the medicinal principle in the white hellebore, Veratrum 
album,and the colchicum autumnale or meadow saffron,plants which have 
a peculiar acid nature caused by the union of the alkaline principle with 
gallic acid. 

Emetia is the alkaline principle which gives ipecacuanha its emetic 
properties. 

777. Almost every plant distinguished for energetic action may proba¬ 
bly be found to owe its powers to some peculiar alkaline principle. Thus 
in the Atropia belladona or deadly night shade, has been discovered the 
alkali called Atropia , which, with acids forms salts of a peculiar kind, 
giving off from their watery solutions vapors which produce giddiness, 
violent headache, and dilatation of the pupil of the eye. From the black 
henbane Hyoscyamus niger is obtained an alkali called Hyosciamia. From 
the Digitalis or fox glove is obtained Digitalia which seems to possess the 
concentrated medicinal virtues of the plant; and from the Datura Stra¬ 
monium is obtained the alkali Daturia. These vegetable alkalies were at 
first distinguished by the termination ine as quinine , morphine, Emetine , 
&c. But the termination in a, is generally adopted, as being in confor¬ 
mity with the other alkaline substances, potassa, soda, magnesia, &c. 

Vegetable substances which contain Hydrogen in excess , as oils y 

resins , <Sfc. 

778. Substances which contain an excess of hydrogen are 
generally oily, resinous, alcoholic or etherial; being also abun¬ 
dant in carbon, they are very fusible and combustible. When 
heated in a retort many of them volatize without any change in 
their constitution, others decompose, producing large portions of 
oil and a carbonous residuum. When exposed to a high temper¬ 
ature in a porcelain tube, they all suffer ultimate decomposition, 
produce carburetted hydrogen gas, carbon, and oxide of carbon. 
Most of these substances are insoluble, or nearly so, in water, 
but very soluble in alcohol. 

oils. 

779. Oils are of two kinds, fixed or fat oils , which are not 

777. Energetic action of plants. To what owing ? Atropia. Hyos¬ 
ciamia. Digitalia. Daturia. 

778. Nature of vegetable substances which contain hydrogen in ex¬ 
cess. Effects of heat upon these substances. 

779. Two kinds of oils. 





FIXED OILS. 


341 


volatile, and give a permanently greasy stain to paper : and vola¬ 
tile or essential oils , which w hen dropped on paper may be dissi¬ 
pated or volatilized by a gentle heat. 

Fixed Oils. 

J l *’ 4 ' " T*.\ '* *l|t> 

7S0. Fixed Oils are chiefly obtained from the seeds of plants, 
and mostly from the dicotyledonous kinds ; as the almond and 
various kinds.of nuts, linseed (flax seed), &c. The oil of olives 
or common sweet oil, is extracted from the pulp which surrounds 
the olive nut. 

r l hese oils are usually procured by subjecting the crushed seed 
or pulp gently heated, to great pressure. It may also be'pro¬ 
cured by the action of boiling water upon the pulverized oily 
seeds. 

The fixed oils, with few exceptions, are fluid at the common tempera¬ 
ture. They usually swim on water, but sink in alcohol. They combine 
with alkalies or metallic oxides, forming soaps which are soluble or in¬ 
soluble according to the nature of the oxide. When exposed to the ac¬ 
tion of the atmosphere they absorb oxygen, become thick and rancid, 
and redden vegetable blues. Such as dry so hard as not to stain paper 
are called siccative or drying oils ; linseed oil is of this kind, and hence 
its use in painting* Dry ing oils mixed with lamp black form printer’s 
ink. During the drying process large portions of oxygen are absorbed. 
This absorption is sometimes so rapid, and causes the disengagement of 
so much free caloric, that light, porous, combustible matters, such as 
lamp black, hemp, cotton and the like may be kindled by it. “ Substan¬ 
ces of this kind moistened with linseed oil, have been known to take 
fire or produce spontaneous combustion within 24 hours, a circumstance 
which has been repeatedly the cause of extensive fires in ware houses 
and cotton manufactories.” (Turner.) 

Though fixed oils do not unite with water, they may be suspended in 
it by the aid of sugar or mucilage, forming an emulsion. Sulphur and 
phosphorus aided by heat, dissolve in the fixed oils ; and the solution 
with sulphur may be crystalized on cooling. Iodine and chlorine absorb 
r a portion of the hydrogen of the fixed oils, and form hydriodic and hy¬ 
dro-chloric acids. Potassium and sodium have little action upon these 
oils; though in time they absorb a small portion of their oxygen, and 
when oxidated thus form with them a soapy compound. Sulphuric acid 
thickens the fixed oils; strong nitric acid acts so forcibly upon them as 
sometimes -to produce combustion. Oxide of lead or litharge, heated 
with oil produces a drying liquid used as oil varnish ; Olive oil with 
the same oxide forms the diachylon plaster. Oils aid in the oxidation of 
metals ; oiled copper soon becomes green, showing the presence of the 
carbonate of copper. 


780. Fixed oils, from whence obtained, &c. Properties of the fixed 
oils. Drying oils. Effects sometimes produced by the rapid absorbtion 
of oxygen, by these oils. Emulsion. Action of sulphur, phosphorus, 
iodine and other substances with the fixed oils. Effect of oils with met¬ 
als. Soaps, volatile liniment, 4"C. 



342 


ORGANIC CHEMISTRY. 


Soaps of various kinds are formed by the union of oils with alkalies. 
Volatile liniment is a mixture of ammonia and olive oil. Tlieir affinity 
is such that, to make this compound, it is only necessary to put the two 
substances m a vessel together, and agitate it to promote their combina¬ 
tion. Common domestic soap is made of animal oil or fat combined with 
alkali; but the finer kinds of soap are often made with vegetable oils. 

781. The principal fixed oils are linseed oil, obtained from flax-seed, 
and used with litharge for paints, varnishes and printer’s ink, Olive oil , 
from the fruit of the olive tree ; (the purest kind being used for the 
table, the inferior for soap and for lights), Almond oil used in medicine ; 
and rape-seed oil from Bressica rapus, the turnip;) mustard seed and 
sunflower seed oils are cheap and much used by leather dressers; Oil of 
lean from the seeds of an East Indian plant is used for absorbing the vol¬ 
atile oils of aromatic plants. The perfumed oil is dissolved in alcohol 
and water is added to the mixture ; the alcohol uniting with the water, 
disengages the volatile oil which float's on the top, and may be collected 
for the perfumer. Palm oil is used in warm countries for food, and export¬ 
ed for medicinal purposes, and to form the finer kinds of soap. Cocoa 
butter is not liquid at the common temperature ;, it has the flavor of choc¬ 
olate. Castor oil from the Ricinus communis is very valuable in medi¬ 
cine. It does not congeal, but at a temperature pauch below zero. 

Volatile or Essential Oils. 

782. The volatile oils are the aromatic principles of plants 
which sometimes are confined to the flower,leaves, bark, or root, 
and sometimes diffused through the whole: but seldom contain¬ 
ed in the cotyledons of seeds which furnish most of the essen¬ 
tial oils. The volatile oils may be obtained by distilling the 
plant with water. 

The operation of distilling plants is as simple as that of making fruit 
preserves, and might furnish an agreeable and feminine employment to 
women. Every lady who has roses in sufficient quantity may manufac¬ 
ture rose water of a much better quality than that which is generally 
sold. A small distillery apparatus may be placed over a portable fur¬ 
nace with rose petals in the boiler covered with water ; the aromatic 
principle of the rose passes over with the distilled water into the recipi¬ 
ent. This product must be returned to the boiler and anew portion of 
the petals of the rose added, and a stronger product is next obtained. 
The opetation must be repeated several times before the water becomes 
strongly impregnated with the aromatic properties of the rose. The 
essential oil of the rose will appear when the water is cool, in very mi¬ 
nute quantities on the surface. But the proportion of oil in this flower 
is so-small that great quantities of its petals are requisite for obtaining a 
very little oil. As ,the rose leaves drop off they may be collected and 
dried or preserved by putting them into a large vessel and sprinkling 
them with salt. The salt will not come over with the product of distil¬ 
lation, nor disengage its elements. Other aromatic plants may he distill¬ 
ed in a similar manner. In India the.oil or -uttar of roses is obtained by 


781. Principal fixed oils. 

782. Situation of the volatile oils in plants. How obtained P Manu¬ 
facture of rose-water. Attar of roses. 



VOLATILE OILS. 


343 


filling large casks with rose petals, covering them with water, and pla¬ 
cing them in the sun, after a few daj^s, particles of oil appear floating on 
the surface. These are collected and put into the small bottles, which 
are sold in the shops. In some cases, as in the rose, jessamine and lilly 
of the valley, the water which passes jinto the recipient in distillation 
will be strongly impregnated with the aroma of the plant, while no oil 
may appear on its surface when cold. Thus rose-water, though not 
visibly containing any oil, owes its aromatic property to a very small 
portion of essential oil, dissolved by the water, in the distilling process. 

783. Essences are essential oils much diluted with alcohol, in 
which they readily dissolve ; twenty or thirty drops of essence 
do not usually contain more than two or three drops of the es¬ 
sential oil ; in medicine therefore it is important to distinguish 
between the two, as over doses of the volatile or essential oils 
have thrown persons into convulsions, and in some instances 
caused death. Even the strong odor of flowers in a confined 
room is unhealthy, on account of the exhalation of volatile oils. 
These oils are generally more energetic than the fixed oils ; they 
are odoriferous, with a hot aromatic taste. Some are colorless, 
many are yellow, some are green and blue. They are all very 
volatile and inflammable. They readily absorb oxygen from the 
air, and become thick. They do not easily combine with sali¬ 
fiable bases. With nitric acid they often inflame and burn bril¬ 
liantly. The most important of the volatile oils are those of 
turpentine, cloves, nutmeg, lavender, cinnamon, peppermint, an- 
nise, and chamomile. 

784. The oil of turpentine is procured by distilling turpentine. When pu¬ 
rified it is called spirits of turpentine. This according to the French 
chemists, is susceptible of crystallization by long exposure to the air. 
It is used in varnishes, and in medicine. It boils at 324°F. It is not 
knowfi whether the volatile oils consist of two or more'ultimate princi¬ 
ples. Dr. Saussure found no oxygen in the oils of lemon and turpentine. 
By absorbing oxygen they become inodorous. 

Camphor may properly be ranked with the essential oils, as it is odor¬ 
ous, inflammable and volatile. The camphor of commerce is chiefly ex¬ 
tracted from the Laurus Camphora which grows in Japan and the East 
Indies. The roots, branches, and leaves are cut into small pieces and 
distilled with water. The camphor which is thus obtained is in the form 
of green porous masses. It is transported in this state and called crude 
camphor. It is purified by sublimation ; its odor is strong, but agreeable 
and refreshing, and its taste acid and pungent. It is not decomposed by 
the air, but in lime wholly disappears by vaporization. It is soluble in 
alcohol and ether. It burns brilliantly in oxygen gas, producing cam¬ 
phoric and carbonic acids. It is lighter than water, its specific gravity 
being 0.980. It is insoluble in water. When a few drops of a solution 
of camphor in spirits is put into a tumbler of water, the water and spirits 
unite and camphor is precipitated. Proust obtained a crystalline pro- 


783. Essences. Properties of volatile oils. Principal volatile oils, 
c. 

784. Oil of turpentine. Camphor. Coumarin. 




344 


ORGANIC CHEMISTRY. 


duct from thyme, lavender, and some other labiate flowers which he sup¬ 
poses differs little from camphor. Much of the camphor of commerce is 
obtained from a large tree found chiefly in the islands of Borneo and 
Sumatra, which when old yields it in the form of solid concretions; 
from the young trees it is obtained by distillation. The uses of cam¬ 
phor in medicine are well known. Camphoric acid which results 
from the action of nitric acid on camphor, unites with salifiable bases 
forming salts called Camphorates. 

Coumarin is a peculiar, odoriferous, volatile principle derived from the 
Coumarouna odorata or Tonka bean. It has a peculiar aromatic odor, 
and is supposed to be the aromatic principle of the Tonka bean. It is 
obtained in a crystalline form like camphor, differing in this respect from 
the volatile oils ; but other properties being analogous, they may be 
properly noticed under this head. 

RESINS. 

785. Resins are the thick juices of certain plants, and are of¬ 
ten found combined with essential oils, which give them their 
peculiar taste and odor, and render them soft. The resins are 
non-conducteis of electricity, but become negatively electrified, 
or acquire negative electricity on being rubbed. Exposed to 
the action of fire, they burn with a yellow flame and much 
smoke. They are insoluble in water, but soluble in alcohol, oils, 
and solutions of potassa and soda. With the two latter they 
form a kind of soap. They are not decomposed by air. Nitric 
acid rapidly decomposes them, much gas is disengaged, and a 
compound results which resembles tannin. The resins are 
composed of a great proportion of carbon, some hydrogen, and 
a small quantity of oxygen. 

786. The resin of pine has been oxidized by Gay Lussac and Thenard, 
100 parts of which were found to contain 

Carbon, 75.944 

Hydrogen, 10.719 

Oxygen. 13.337 

100.000 

The juice of the different kinds of pine, called turpentine , consists 
chiefly of resin combined with the volatile oil .of turpentine. The resin¬ 
ous products of the different species of cone-bearing trees are distinguish¬ 
ed by various names. Common turpentine is obtained by making incis¬ 
ions in the pine trees, and hardening the juice which flows out by ex¬ 
posure to the air and sun. Burgundy pitch is from the Norway spruce 
and larch. Tar is melted out from the resinous trees by a smothered fire 
resembling a coal pit. Lac is a red concretion caused by the puncture of 
an insect upon the branches of the Banyan, Fig, and Rhamnus jugaba of 
the East Indies. It consists mostly of resin with coloring matter and 
wax. Shell lac contains more resin and less coloring matter than Stick 


785. Cause of the peculiar taste of the resins. Properties of resins. 
Composition. 

786. Resinous products of the pine. Lac. Copal. Amber. 




RESINS. 


345 


lac. Shell lack in India is cast into beads, and other ornaments; it is 
used for red sealing wax. Stick lac is used in dyeing. Copal is a bril¬ 
liant, transparent resin which is chiefly used for varnishing. It is brought 
from South America and the East Indies It is susceptible of becoming 
highly electrified by friction. Amber resembles copal in appearance; it is 
supposed to be of vegetable origin, though found in sand. It is some¬ 
times found in beds of bituminous coal, and enveloping vegetable sub¬ 
stances. It often contains insects in good preservation. It was in this 
substance that electrical phenomena were first observed; its ancient 
Greek name was Electron. It consists of a volatile oil, succinic acid, 
resin, and a bituminous principle. 

787. Balsams are resins CQntaining so much essential oil as to 
render them fluid, or nearly so. They are not proximate prin¬ 
ciples, but rather consist of several of these principles united ; 
as resin, benzoic acid, essential oil. They are divided into liquid , 
of which the balsam of copaiba and styrax are examples, and 
solid, as benzoin and dragon’s blood; the latter is used in making 
red varnish. 

788. Gum resins contain gum, resin, wax, volatile oil, and ex¬ 
tractive matter. They are not therefore distinct proximate princi¬ 
ples. They ponsist of resin, volatile oil, gum and extractive matter; 
the two former principles are soluble in alcohol, the two latter in 
water ; they therefore dissolve readily in spirits or diluted alco¬ 
hol. The gum-resins are valuable in medicine. Among the 
most important are myrrh , aloes , assafoetida , gamboge and guaicum. 

789. Caoutchouc, Indian Rubber,ox gum elastic is the concrete juice of the 
Urceola elastica and Jatropha elastica, plants of South America. It is also 
obtained from some of the trees peculiar to hot climates, and is said to 
have been prepared from the dried juice of the milk weed,* (asclepias.) 
This substance is white, when not blackened by smoke as is common in 
its preparation ; it is soft, flexible, very tenacious and elastic. It melts 
readily and burns with a bright flame, leaving little residuum. It is in¬ 
soluble in water, alcohol, alkalies and acids. The volatile oils are its 
proper solvents. The purified Naphtha from coal tar dissolves it, and being 
a cheap article may be profitably employed in Indian rubber manufactories. 
It must contain some nitrogen since by destructive distillation it yields 
ammonia. 

790. Wax is extensively diffused in nature. It is found as a varnish on 
the surface of the leaves of plants, in the pollen of flowers, and in many 
trees. The wax of bees appears not to be wholly of vegetable origin, 
being composed also of some animal secretion. Huber found that bees 

* The late Mr. H. Eaton, formerly professor of Chemistry in the 
Transylvania University, Kentucky, informed the author that he had 
succeeded in preparing from the milk of the common milk-weed (As¬ 
clepias,) a substance which could not be distinguished from the gum- 
elastic of commerce. 

787. Balsams. 

788. Gum resins. 

789. Caoutchouc or Indian Rubber. 

790. Wax. Wax of the myrica cerifera, &c. Properties of wax. Con¬ 
stituent principles of wax. 

30 




346 


ORGANIC CHEMISTRY. 


which were fed solely on sugar produced wax in as great quantities, as 
those which had access to flowers. The berries of the Myrica cerifera or 
bayberry , contain large portions of wax; it is aromatic, of a pale green 
color, and is sometimes mixed with tallow to render candles more firm; 
it has been called bayberry talloio. Wax is usually more or less colored, 
and may be bleached by exposure to the sun and air, and by the action of 
chlorine. Thus bees wax which is yellow and has an aromatic smell, be¬ 
comes, by bleaching very white and destitute of odor. Wax melts at 
154° F., it is insoluble in water, dissolves in warm ether and alcohol, but 
precipitates when cold. It is easily dissqlved by the fixed and volatile 
oils. It has been found to consist of two principles, one of which called 
cerin is soluble, the other called myricin is insoluble in alcohol. 


LECTURE XXXIII. 

ALCOHOL, ETHER, &C. 

, '• ^ - 

ALCOHOL. 

791. Is a colorless, volatile liquid, of a strong odor and a 
burning taste. It is the intoxicating ingredient in all kinds of 
spirits, wine, cider and beer. It does not exist ready formed in 
plants, but is produced by the vinous fermentation. Fermented 
liquids have been known from the remotest periods of history ; 
though distilled liquors were first prepared by an Arabian Alchy- 
inist in the tenth century ; though they were little known until 
some hundred years after. 

792. On account of its volatile nature, alcohol is readily obtained by 
distilling fermented liquors. Common alcohol, contains some water, 
which when abstracted by substances that have a strong affinity for wa¬ 
ter, leaves pure alcohol, called rectified spirit , and when supposed to be 
entirely free from water absolute alcohol. The purer the alcohol the 
lighter it is; thus the specific gravity of spirits is a test ol their strength, 
or the proportion of pure alcohol they contain. Common alcohol has, at 
the temperature of60° F.,a specific gravity of 0.86, rectified spirit, 84, 
and absolute alcohol of 0.79. The hydrometer* is the instrument used to 
test the specific gravity of spirits. Alcohol boils at a temperature as low 
as 176° F. It produces cold during evaporation, hence the cooling effect 

* See the author’s Familiar Lectures on Natural Philosophy, page 165. 

791. Physical properties of alcohol. How produced ? Distilled li¬ 
quors first known. 

79&. Mode of obtaining alcohol. Rectified spirit and absolute alcohol. 
Specific gravity of alcohol. Its boiling point. Effect of its evaporation, 
on surrounding bodies. Freezing point of alcohol. How is it useful in 
thermometers ? 





ALCOHOL. 


347 


of bathing the head and limbs of fevered patients in spirits. No degree 
of cold has yet been known, with certainty, to freeze alcohol, though Mr. 
Hutton asserted that it congeals at 90° below zero of Fahrenheit’s ther¬ 
mometer. Other Chemists have found it to remain liquid at 91°. When 
it is half water it freezes at GO 3 below zero. On account of the property 
of alcohol to remain liquid at the extreme degree of cold where mercury 
freezes, it is used in thermometers which are designed to measure in¬ 
tense cold. 

793. As alcohol burns without smoke or residuum, the spirit lamp is 
much used in laboratories. Attempts have been made to introduce alco¬ 
hol into common use, in the place of oil, for lamps; but its use has been 
found dangerous, owing to its great inflammability ; as when accidentally 
spilled when burning, its whole surface will burst forth into instant flame. 
The products of its combustion are water and carbonic acid. The flame 
of alcohol directed upon lime or chalk produces a most vivid light, and is 
therefore much used in light-houses. It may be inflamed by the electric 
spark. 

794. Alcohol has great solvent powers. It dissolves most of the vege¬ 
table principles, as the essential oils, resins, balsams, and most of the 
vegetable alkalies and acids (but not many of the fixed or animal oils.) 
It dissolves potassa, soda, and ammonia, but not the earths or metallic 
oxides. Phosphorus, sulphur, and iodine are sparingly soluble in Alcohol. 
Chlorine produces with it an oily substance, accompanied with muriatic 
and carbonic acids. This oily matter seems to be a combination of chlo¬ 
rine and per-carburetted hydrogen. When equal parts of alcohol and wa 
ter are mixed, there is an elevation of temperature, and consequent ex¬ 
pansion of the liquids; this mixture constitutes proof spirit. 

795. When alcohol is heated in a porcelain tube, the products of the 
decomposition are carburetted hydrogen, carbonic oxide and water. Ac¬ 
cording to the analysis of the younger De Saussure, the ultimate elements 
of alcohol are 

Carbon 2 Equiv. =12 parts in 100 52.17 

Oxygen 1 “ = 8 “ “ 34.79 

Hydrogen 3 “ = 3 “ “ 13.04 

Equiv. of alcohol 23 100.00 

These elements are in the proportion to form olefiant gas and water ; 
there are two equivalents of carbon, 1 of oxygen and 3 of hydrogen. 
Olefiant gas requires 2 equivalents of carbon X to 2 of hydrogen. W T ater 
requires 1 equivalent of oxygen X 1 of hydrogen. 

796. It was formerly asserted that alcohol did not exist ready 
formed in wine, but was generated by heat, during the distilling 
process. Mr Brande determined this question by obtaining 
alcohol from wine without the aid of heat. He precipitated the 
acid, and extracted coloring matter by the sub-acetate of lead, 
and then absorbed the water from the alcohol by dry carbonate 

793. Spirit lamp. Danger attending its use in lamps. Products of 
the combustion of alcohol. Its use in light-houses, &c. 

794. Solvent powers of alcohol. Use of Spirit. 

795. Products of the decomposition of alcohol. The elements com¬ 
posing alcohol are in the proportion to form olefiant gas and water. 

796. The question settled with respect to the existence of alcohol 
ready formed in wine. 





348 


ORGANIC CHEMISTRY. 


of potassa. Pure alcohol rose on the surface. The strong wines, 
Madeira, Sherry, Port, &c contain from 18 to 25 per cent of al¬ 
cohol, and cider, ale and porter from 4 to 10 per cent. 

797. The action of the acids on alcohol produces a peculiar 
substance called ether, which varies in its properties w ith the 
acid employed. Alcohol also like water, forms with certain 
bodies, definite crystalline compounds ; these are called alcoates * 

When the anhydrous chlorides of calcium, manganese and zink or the 
nitrates of lime and magnesia are heated with anhydrous alcohol, the 
compound on cooling will assume a crystalline form. A very small quan¬ 
tity of water would prevent the crystalization. The crystals are deli¬ 
quescent, soluble both in water, and alcohol, and readily fuse in their 
water of crystalization. 

798. Alcohol, on account of its great solvent power, and other 
peculiar properties is an agent of great importance in medicine 
and the arts; but however indispensible, when taken in any 
considerable quantities into the animal system it has a poisonous 
and fatal tendency ; and this, under whatever disguises it may 
be presented. 

ETHER. 

799. The ethers are inflammable volatile liquids, formed by 
the action of alcohol with various acids. Sulphuric ether, or the 
compound formed with alcohol and sulphuric acid was formerly 
the only ether known. But as alcohol is found capable of form¬ 
ing many ethereal compounds, they have been divided into three 
classes. The 1st contains those which are composed of oxy¬ 
gen, carbon and hydrogen ; the acid with which they are formed 
being decomposed^ and the elements so combined as to form 
water and olefiant gas, as sulphuric, phosphoric, and arsenic 
ethers. 2d. Those ethers which are formed with acids contain¬ 
ing hydrogen instead of oxygen ; these consist of the hydracid and 
olefiant gas ; as hydrochloric and hydriodic ethers. 3d con¬ 
tains ethers in which the oxacid is united with alcohol as in nitric 
ether and acetic ether. 

Ethers of the First Class. 

800. Sulphuric ether has long been known and is much used 

* As crystals containing water are called hydrates. 

797. Action of acids with alcohol. Alcoates or crystals containing 
alcohol instead of water. 

798. Use of alcohol and its effects on the animal system. 

799. Division of etherial compounds into three classes. 

800. Sulphuric ether. Preparation. 



ETHER. 


349 


in medicine and the laboratory. It is the most important of the 
ethers^ and was long considered the only one. 

It is formed by pouring strong sulphuric acid upon an equal weight of 
rectified alcohol in a. glass retort. This mixture, being heated over a 
sand bath, boils and ether is generated which rises in a recipient kept 
cool by ice, or clothes wet in cold water. The operation is continued 
until white vapors appear in the retort; after this, sulphurous acid gas, 
with a peculiar yellowish liquid, called ethereal oil, and the sweet oil of 
wine (sulpho-innic acid,) begin to pass over ; longer continuance of the 
heat produces olefiant gas. The ether thus obtained is impure ; it is 
rectified by adding to it l-15th ofits weight of potassa, which absorbs the 
sulphurous acid and the ethereal oil. It is then decanted and agitated 
with water, which unites with any alcohol that may be in the ether, and 
this has the property of dissolving a small quantity of water; the latter 
may be abstracted by gently distilling the ether with the chloride of 
Calcium. 

801. It was long believed that sulphuric acid transformed alco¬ 
hol into ether, by taking from it a certain quantity of water ; and 
the composition of ether seemed to favor the theory. At present, 
the decomposition of sulphuric acid during the process for ob¬ 
taining ether is admitted, and also that alcohol consists of one 
part of olefiant gas and one of water, and ether of two of olefiant 
gas and one of water. The sulphuric acid by uniting with one 
equivalent of the water of the alcohol, converts it into ether. 

802. Sulphuric ether is without color, it has a strong and fra¬ 
grant odor, and a hot and sharp taste. According to Gay Lussac 
it does not transmit the electric fluid. It reflects light strongly ; 
is perfectly limpid and fluid. Its specific gravity when purest is 
about 0.70 ; but that of the shops is 0.74, and sometimes greater, 
owing to the presence of alcohoi. 

Ether is very volatile, being at 96° F. under atmospheric pres¬ 
sure ; and at 20° below zero in a vacuum, absorbing caloric so 
rapidly from surrounding bodies as to freeze water, and even 
mercury. It freezes at 46°. Its vapor has a density of about 
2.58, air being 100. It flows through a capillary tube nearly 
four times as fast as water, and eight times as fast as alcohol ; 
but does not rise so high by capillary attraction as either of the 
other two fluids. It is highly inflammable, burning with a blue 
flame ; its vapor forms a mixture with the oxygen gas which 
explodes by an electric spark or on the approach of flame. 

803. “ When a coil of platinum wire is heated to redness, and then sus¬ 
pended above the surface of ether contained in an open vessel, the wire in¬ 
stantly begins to glow and continues in this state until all the ether is 
consumed. During this slow combustion, pungent acid fumes are emit¬ 
ted, which if received in a separate vessel, condense into a colorless li¬ 
quid possessed of acid properties. Mr. Daniell, who prepared a large 


801. Explanation of the action of sulphuric acid upon alcohol. 

802. Properties of sulphuric ether. 

803. Substance named by M. Daniell lampic acid. 

30 * 



350 


ORGANIC CHEMISTRY. 


quantity of it, was at first inclined to regard it as a sour acid which, in 
reference to the mode of obtaining it, he called lampic acid ; but he has 
since ascertained that the acidity is owing to the acetic acid, which is 
combined with some compound of carbon and hydrogen different both 
from ether and alcohol. Alcohol when similarly b limed likewise yields 
acetic acid.”— Davy. 

804. Ether is somewhat less powerful as a solvent than alco¬ 
hol, though most of the substances which dissolve in the latter, 
are dissolved in the former. It has no action upon the fixed al¬ 
kalies, but unites wfith ammonia. It dissolves Indian rubber 
wfith great facility. When exposed to the light it gradually ab¬ 
sorbs oxygen, and becomes sour, which is supposed to be occa¬ 
sioned by the formation of acetic acid. Ether is very inflammable, 
burning with a blue flame; a lump of sugar filled with ether 
thrown into a vessel of boiling water, forms a burning fountain, 
by lighting it wdth a taper. Chlorine with ether produces spon¬ 
taneous combustion and explosion. 

805. Ethers of the second class, axe muriatic, hydriodic, &c. Muriatic 
ether is obtained by distilling a mixture of equal parts of muriatic acid 
and alcohol in a glass retort connected with Woulfe’s apparatus. The 
first flask contains water, the others are empty and surrounded with ice. 
At a great heat the distillation commences, the other acid gas parts with 
its superfluous acid and alcohol in the water of the first flask and is con¬ 
densed in the others This ether is composed of equal volumes of 
muriatic acid and olefiant-gas, united without condensation, as its specific 
gravity is equal to the sum of the specific gravity of the two gases ; viz. 
muriatic acid having the specific gravity of 1.278X to alcohol having the 
specific gravity of 972=2.250, which is very near the specific gravity of 
muriatic ether, when compared with atmospheric air. It is even more 
volatile than sulphuric ether ; boils by the heat of the hand, producing by 
its evaporation a sensation of coldness. It burns with a green flame, 
disengaging muriatic acid gas. From its composition it is apparent that 
it contains no oxygen gas. 

806. Hydriodic ether is obtained by distilling hydriodic acid and alco¬ 
hol. The product which collects in the recipient being washed with 
water, the ether collects in milky globules, which, when united, form a 
transparent liquid. After a few days, a small portion of iodine is set free, 
and the liquid becomes rose colored; potassa, by uniting with this io¬ 
dine, renders the liquid again colorless. When poured on hot charcoal, 
it gives off the purple vapors peculiar to iodine. 


804. Solvent powers of ether, &e. 

805. Ethers of the second class. Muriatic ether. 

806. Hydriodic ether. 



NITRIC ETHER. 


351 


807. The ethers of the third class , are 
nitric, acetic, &c. 

Nitric ether is made by distilling equal 
weights of alcohol and nitric acid : but the 
mutual action of the two substances is so vi¬ 
olent as to render the process dangerous. 
The alcohol must be added in small quanti¬ 
ties. “A, represents a Woulfe’s bottle; 
13, a receiver ; c, c, glass funnels ground to 
their necks, and glass rods ground to the 
funnels ; the acid being in one funnel and 
the alcohol in the other.” (Silliman’s Ele¬ 
ments.) 

Nitric ether is of a yellowish color, has a strong odor, and burning 
taste. It is heavier than alcohol, and lighter than water. It evinces 
acid properties by reddening litmus, and may be neutralized by potassa, 
with which it forms a hypo-nitrate of potassa. With alcohol it forms the 
sweet spirit of nitre, which is valuable in medicine. Its ultimate ele¬ 
ments are carbon, nitrogen, hydrogen, and oxygen, in proportions to 
form 5 equivalents of olefiant gas, 1 of hypo-nitrous acid and 1 of wa¬ 
ter. 

Acetic ether is formed in a manner analogous to the ether already de¬ 
scribed. It inflames on the approach of a burning substance, reproduc¬ 
ing acetic acid. It has an agreeable odor, dissolves in alcohol, and 
forrfts a stimulating medicine. 

There are ethers formed with alcohol and the vegetable acids ; or the 
benzoic, citric, oxalic, &c But none of them are of use. 


Fig. 124. 



LECTURE XXXIV. 

SUGAR, STARCH, GUM, &C. 

SUGAR. 

808 Under the head of sugar are included those substances 
which have a sweet taste, and when brought in contact with 
water, and a very small proportion of yeast, produce alcohol, by 
means of the vinous fermentation. This proximate principle 
is extensively diffused throughout the vegetable kingdom. 
Plants which contain it are called saccharine. Sugar is crystal- 
lizable either more or less perfectly, sweet, inodorous and very 

807. Nitric ether. Properties of nitric ether. Sweet spirit of nitre. 
Ultimate elements of nitric ether. Acetic ether. 

808. General properties of sugar as produced from various substan¬ 
ces. 















352 


ORGANIC CHEMISTRY. 


soluble in water, alcohol and other liquids. Pure sugar is hard, 
firm, and not acted upon by the air. Moist sugar is always im¬ 
pure. Sugar is phosphorescent in the dark, by means of fric¬ 
tion. Sulphuric acid decomposes sugar, and disengaging char¬ 
coal, forms water, and acetic, or some other vegetable acid. 
When nitric acid is mixed with sugar, both substances decom¬ 
pose, and oxalic acid is formed. Its solution is not precipitated, 
by the sub-acetate of lead, which furnishes a test for the presence 
of sugar in vegetable substances. Owing to the quantity of car¬ 
bon in sugar it is very inflammable, and gives off a peculiar 
odor in burning.* It forms but feeble combinations with metal¬ 
lic oxides, Lime, baryta or strontia boiled with sugar becomes 
bitter, astringent, and uncrystallizable. By adding a sufficient 
quantity of an acid to neutralize the oxide, the sugar resumes 
its properties. 

809. The results in the decomposition of sugar being found to vary, it 
was at length discovered that its constituent principles varied in some 
degree in different vegetables 3 thus the sugar of the cane affords more 
carbon than that of the grape. According to Gay Lussac the sugar of 
the cane, is, in weight, composed of 


Carbon 42.47 

Qxygen 50.63 

Hydrogen 6.90 


100.00 

While that of the grape was found to consist of 
Carbon 36.71 

Oxygen 56.51 

Hydrogen 6.78 


100.00 

The specific gravity of sugar is about 1.6 water being 1 

810. Sugar of the cane. The sugar cane is the arundo saccha - 
rifera of botanists. This plant furnishes the greater part of the 
sugar of commerce. Although sugar was manufactured in In¬ 
dia in the days of Alexander the Great, who is said to have 
brought the knowledge of it to Macedon, yet it was scarcely 
used in Europe, except in medicine until the discovery of the 
West Indies, where the most extensive sugar manufactories now 
exist. 

* The carbonaceous, acetic, and other vapors which exhale from burn¬ 
ing sugar, probably possess some medicinal powers 3 and the practice of 
sprinkling sugar in the domestic warming pan, when used for warming 
the beds of those who are suffering under rheumatic affections or sudden 
colds, is founded on more substantial reasons than “ old wive’s whims.” 


809. Constituent principles of sugar, &c. 

810. Sugar of the cane. Manufacture of sugar. 





SUGAR OF BEET. 


353 


Sugar is obtained from the expressed juice of the sugar cane, by slow 
boiling, during which process the aqueous particles evaporate. Lime 
water is then added to the liquor when boiling, to neutralize the oxalic, 
and other vegetable acids, and to separate extractive matters and other 
impurities, which, uniting with the lime, rise and form a thick scum on 
the surface; the liquor below, is drawn off, by means of a syphon, 
into large shallow vessels, where an imperfect crystallization takes place. 

811. Maple sugar. From the sap of the sugar-maple tree 
Acer Saccharinum , is manufactured, to a considerable extent, a 
valuable domestic sugar in many of the northern United States. 

Incisions or perforations are made in the trees at that season of the 
year when the sap runs most abundantly ; this is in early spring, with 
the first warm beams of the sun. The sap of the maple is about one 
sixth as rich as the juice of the cane ; four pounds of maple sap yielding 
one pound of sugar. When suitably evaporated, by boiling in large ket¬ 
tles, and permitted to cool, it forms a granular solid mass. This may be 
purified so as to resemble loaf sugar, in whiteness and fineness ; but is 
generally used in a less refined state. 

The maple juice boiled down to a consistence somewhat less than 
common West India molasses is used for similar purposes; and when 
evaporated to a thick syrup resembling liquid honey, it is sometimes used 
for the table, as a substitute for sweetmeats. 

812. Sugar of beets. The beetroot is found to be rich in sugar. 

In France, are many large manufactories of this article. Chaptal, 
Count of Chautaleup, a peer of France, a theoretical, and practical 
Chemist, and a farmer, says, “ from' twelve years experience 1 have 
learned in the first place that the sugar extracted from beets differs from 
that of the sugar canb neither in color, taste, nor crystallization ; and 
in the second place that the manufacture of this kind of sugar can com¬ 
pete, advantageously with that of the sugar cane. These facts being es¬ 
tablished and acknowledged, it may be asked, whether the manufacture 
of beet sugar would be advantageous to agriculture. The cultivation of 
beets need not prevent the production of a single kernel of wheat, since 
this may be made an intermediate crop, and the sowing of it commenc¬ 
ed as soon as the beets shall be dug. The crops of corn are better upon 
beet lands'than upon others, because, the beets have divided and loosen¬ 
ed the earth, and the weqdings have cleared it of strange plants. 

The operations upon 10.000 pounds of beets per day place at the dis¬ 
posal of the agriculturist about one and one fourth tons of mush which is 
the best kind "of food for horned cattle. The working of the beet being 
performed in winter, furnishes employment to the men and cattle of a 
farm, at a season when they are too often condemned to idleness. The 
prosperity of an establishment pf this kind depends upon its being con¬ 
nected with rural labors. This kind of manufacture is out of place in 
cities and villages, because buying beets is more expensive than raising 
them, the mush cannot be rendered so productive, and labor and fuel 
are more expensive.* 

* See Chaptal’s “ agricultural Chemistry,” for a detailed account of the 
mode of cultivating The beet root, and conducting the beet sugar manu¬ 
facture. This subject is one of interest to the American farmer, and de¬ 
serves attentive consideration with careful experiments. 


811. Maple Sugar. Manufacture of Maple Sugar. 

812. Sugar of beets. Chaptals opinions upon the manufacture of 
beet sugar. 



354 


ORGANIC CHEMISTRY. 


813. Many other succulent roots, as the onion, parsnip and 
carrots also furnish sugar. 

Sugar of grapes , of figs and other ripe fruits contains more or 
less of the peculiar flavor of the fruit derived from other prin¬ 
ciples. It does not crystallize in regular forms, and it is less 
sweet than the sugar from the cane. 

Sugar of mushrooms crystallizes in four-sided prisms ; its taste 
is not pleasant. 

Sugar of Starch is made by forming a paste with starch and 
water and allowing it to stand for some time. Sulphuric acid 
converts starch into sugar. Dr. Saussure found the weight of 
sugar formed was considerably more than that of the starch em¬ 
ployed, from whence he inferred that a portion of the water be¬ 
comes solidified; that the sugar of starch was consequently only 
a combination of sugar with hydrogen and oxygen in the neces¬ 
sary proportions to form water, and that the sulphuric acid had 
no other influence than to increase the fluidity of the aqueous 
solution of starch. 

814. Manna (from a Syrian word mano a gift, being the food given 
by God to the Israelites), exists in the sap of the ash, Fraxinus ornus. in 
the celery and beet plant. It is sweet and crystallizable like sugar, but 
it owes its sweetness to a distinct principle called mannite , which is ob¬ 
tained by dissolving manna in boiling alcohol; the liquor is filtered 
while hot, and on cooling, the manna is precipitated. This principle 
differs from sugar in not fomenting with water and yeast, and of course 
produces no alcohol. 

Honey is composed of two kinds of sugar, the one liquid and uncrys- 
tallizable, the other analogous to the sugar of grapes and crystallizable ; 
these, with mucilage, and an aromatic principle, constitute all the varie¬ 
ties of honey. By mixing honey with alcohol, the liquid sugar may be 
obtained by pressing the solution through a strainer, while the crystalli¬ 
zable principle remains solid. Honey is prepared in the stomach of the 
bee, from the viscous juice and sugar which this insect collects from the 
nectaries of flowers; after remaining a time in this laboratory it is de¬ 
posited in the cavities of the honey comb. Honey varies in quality ac¬ 
cording to the different plants which furnish the materials. That which 
is obtained from the flowers of the tobacco, Stramonium, and others of 
the same natural family, is poisonous. The honey of Mount Hymettus 
and Mount Ida in Greece was celebrated in ancient times for its beauty 
and excellence. The honey furnished by labiate plants, as the thyme, 
balm, <fcc., is of the best kind. Honey is used as food and medicine. 
When united with the vinegar it forms oxymel. Thus the common prepa¬ 
ration of squills is called the oxymel of squills* Dissolved in water, 

* That is, oxymel combined with the juices of a bulbous plant, the Scil- 
la maratima or squills. 

813. Other roots which furnish sugar. Sugar of grapes, figs, &c. Su¬ 
gar of Mushrooms. Sugar of Starch. 

814. Manna. Honey. Sugar of liquorice. 





STARCH. 


355 


honey ferments, and forms a liquor called Hydromel or Metheglen , a pleas¬ 
ant but intoxicating beverage. 

Sugar of liquorice. The substance called liquorice is from the root of 
a plant, the Glycirrhiza gla.bra ; its sweet principle seems to be of a pe¬ 
culiar kind. It resembles amber in appearance and inflammability. 

815. Starchy Farina , or Fecula is one of the most abundant 
proximate principles in nature, existing in the stems, leaves, 
roots and seeds of plants. When pure it is a white powder, in¬ 
sipid, inodorous, insoluble in cold water, alcohol and ether, but 
soluble in boiling water. This solution on cooling takes the 
form of a jelly, in which state it is used by the laundress for 
starching linen. Hot sulphuric acid transforms it into a sugar 
like substance, capable of yielding alcohol by fermentation. 
Nitric acid changes it into malic and oxalic acids. Iodine fur¬ 
nishes the best test for starch, forming with it compounds of a 
blue color; but fighter with smaller portions of iodine. This 
fact is applied in the arts to discover whether goods owe their 
fineness to the texture of the material or a finish of starch; in 
the latter case, a drop of the solution of iodine produces a blue 
spot. 

816. According to Gay Lussac and Thenard, starch is composed of 

43.55 parts of Carbon. 

49.68 “ “ Oxygen. 

6.77 “ “ Hydrogen. 

Starch is usually obtained by grating or bruising the substances which 
contain it, and washing the product with pure water. Its specific gravity 
being greater than that of water, the starch is soon deposited in the form 
of a°white mass, which, when dry, is a soft powder. If a piece of dough 
or wheat flour be enclosed in a linen bag, and pressed with the hand 
while a current of cold water is poured on, the starch or farina will be 
washed out mechanically and subside at the bottom of the vessel, while 
the gluten of the flour is left pure in the bag, and saccharine matter 
and mucilage are in solution. Heat produces with starch peculiar ef¬ 
fects; thus, when dry starch is heated a little above 112 Q , it becomes so¬ 
luble in cold water, and its odor resembles that of baked bread. The ac¬ 
tion of boiling water on starch, as prepared for starching muslin, produc¬ 
es a similar change of properties. By continued heat, and carelul evap¬ 
oration a transparent mass is obtained, soluble in cold water, and resem¬ 
bling horn, this is called amidine*. Starch when exposed to a greater 
heat°than sufficient to produce amidine is converted into a substance 
called gum, and in this state is used by calico printers. 

* So called by the French Chemists from amidon , the French name 
for starch. 


845 . Abundance of starch in vegetables. Properties of Starch. Ac¬ 
tion of Iodine with starch. 

816. Constituent elements of starch. Modes of obtaining starch. Ac¬ 
tion of heat and of boiling water upon starch. 




356 


ORGANIC CHEMISTRY. 


817. We have seen that the constitution of starch differs lit¬ 
tle from that of sugar, and that the former may be easily con¬ 
creted into the latter. This change takes place in the germina¬ 
tion of seeds ; in the process of malting barley, and in vegeta¬ 
bles that have been frozen under certain circumstances : thus 
apples which have, been exposed to the air during severe frosts 
acquire a peculiar sweetish taste. 

818. Of the various kinds of starch, those which are obtained 
from the flour of different kinds of grain, from the potato, and 
green Indian corn are used in the laundrey for starching linen and 
muslin. The Indian arrow root (Maranta arundinaecd) , Sago 
(from the pith of the Cycas circinalis , tapioca, and cassava (from 
the root of the Jatepoha manihot) have the properties of pure 
starch. They are all highly nutritious and valuable as food for 
the sick. In the warm countries which produce the plants from 
which they are obtained, they furnish much of the food of the 
inhabitants. 

GUM AND MUCILAGE. 

819. Gum is an abundant prbduct of vegetables. It is un- 
crystallizable,colorless,inodorous in alcohol, and soluble in water 
with which it forms a gelatinous compound call mucilage . It 
cannot be made to pass through the vinous fermentation. Nitric 
acid changes it to mncic acid. Gum or mucilage is found in all 
the parts of herbaceous plants ; in many roots ; and in all fruits. 
Many trees, particularly those whose fruit is of the dnpe* kind, 
secrete large portions of gum. 

820. The principal gums are 

1. Common gum , obtained from the peach, plumb, cherry 
tree, &c. 

2. Gum arable , which flows naturally from the acacia or mi¬ 
mosa of Egypt, Arabia and other warm countries; this, w 7 ith 
water, forms a clear, transparent mucilage. 

3. Gum Senegal , resembles Gum Arabic except that it is ex¬ 
ported in much larger pieces. 

4. Gum tragacanth , from the Astragalus tragacantha , a shrub of 
Syria, and the islands of the Levant. These are all useful in 
medicine and the arts ; and in some countries they are used as 
food. 

* Having a kernel enclosed within a pulpy substance, as the cherry, 
plum, and peach. 


817. Conversion of starch into sugar. 

818. Uses of starch. 

819. General properties of gum, &c. 

820. The principal gums. Uses of these gums. 



LIGNIA. 


357 


821. Flax-seed, the fruit and seeds of the quince, the bark of 
the slippery elm, and the different species of mallows, all afford 
mucilage when boiled in water. When evaporated to the thick¬ 
ness of syrup the gum is precipitated by alcohol. Mucilage may 
be considered as an aqueous solution of gum, existing naturally 
in ripe fruits, and the leaves and roots of some plants, and formed 
by dissolving gum in water. Mucilage soon becomes sour on 
exposure to the aiv, owing to the formation of acetic acid ; and in 
time this change takes place without access of air, which must 
be owing to the new arrangement of its constituent princi¬ 
ples. 100 parts of gum arabic have been found to consist of 

42.23 parts of Carbon. 

50.84 “ “ Oxygen. 

6.93 “ “ Hydrogen. 

100.00 

Vegetable jelly , such as is obtained from the currant, quince, 
grape, &c., is mucilage combined with different vegetable acids. 

WOOD, LIGNIA, OR WOODY FIBRE. 

822. This is the basis or skeleton of vegetable substances, and 
the most abundant of all the proximate or vegetable principles 
forming about 96 per cent of the different kinds of wood. The 
woody or hard substances of plants contains, in its interstices the 
sap, and other peculiar principles, as the volatile oils, gums, res¬ 
ins, sugar, &c. This substance is found in every part of the 
plant, the root, the stem, leaves, fruit and even the flower. In 
the dry state it may be seen in the shells of almonds and many 
other nuts, even the soft petals of the rose, when deprived of 
their essential oils, mucilage and other extractive matter will be 
found reduced to this hard insoluble substance. 

Lignia for chemical purposes is usually obtained from saw-dust, be¬ 
cause wood thus minutely divided, is in a favorable state to be acted upon 
by the agents which are required to purify it of all foreign matter. Saw¬ 
dust is first digested in alcohol, to dissolve the resinous part, afterwards 
in water which dissolves some salts and extractive matter, then with 
weak muriatic acid, which attacks salts that are insoluble in water, par¬ 
ticularly the carbonate and phosphate of lime. Lignia is white, insipid, 
inodorous, and specifically heavier than water. 

Sulphuric acid decomposes lignia; changing it first into a gum-like 
substance, which, on being boiled, becomes sugar. According to 


82t. Mucilage. Composition of gum arabic. Vegetable jelly. 

822. Abundance of woody fibre, &c. Lignia for chemical purposes, 
how obtained? Properties of lignia, &c. Products of the decomposition 
of wood, by heating in close vessels. Bread made from saw-dust, &c. 

31 




358 


ORGANIC CHEMISTRY. 


Beaconnot all substances which contain lignia, as saw-dust, straw, bark, 
and linen, may be converted to sugar. In heating wood in close vessels, 
acetic (pyroligneous) acid and volatile products are obtained. Among 
these, is a fluid resembling alcohol, called pyruxylic spirit. It burns with 
a blue flame, has a strong and pungent taste, but differs from alcohol in 
not yielding ether when acted upon by sulphuric acid. 

It is found that bread may be made from saw-dust, bark, rags, &c., by 
converting these substances into lignia. The latter when heated in an 
oven, smells like meal or flour of Indian corn. It ferments with leaven, 
and affords a spongy, nutricious bread. The same flour of wood, when 
boiled affords a jelly like that of starch. According to Gay Lussac and 
Thenard, lignia consists of 

Carbon 52 parts. 

Oxygen and Hydrogen in > 48 “ 

proportion to form water. )- 

100 

COMPOUNDS WHICH ARE NOT CONSIDERED AS BELONGING TO THE 
PRECEDING DIVISIONS OF VEGETABLE PRINCIPLES ; AS 
COLORING MATTER, TANNIN, GLUTEN, &C. 

823. Coloring matter. Vegetable coloring matter in found at¬ 
tached to some proximate principle, as mucilage, farina, resin or 
extractive matter ; and its solubility depends on the nature of the 
principle with which it is associated. Coloring matter cannot, 
therefore, be considered as itself a proximate principle. Color is 
a secondary property, dependant on the peculiar arrangement of 
atoms, and of course affected by chemical changes. Thus, we 
have seen in the course of our experiments, color of bodies chang¬ 
ing with new combinations ; a colorless acid transforming the 
blue infusions of flowers to a brilliant red, ancf a colorless alkali 
changing the same blue infusion, to a green color. The process 
of dyeing, depends on chemical principles, but the details of the 
subject belong to the arts rather than to science. 

The coloring matter resides in various parts of plants. In 
some, it is in the flower, in others, in the bark, or the leaves, 
w r ood, or root. It is soluble by various agents according to the 
nature of the proximate principle with which it is associated ; thus 
some colors are obtained by means of alcohol, others by water, 
others by acids, and others by the essential oils. Most vegetable 
colors are decomposed by exposing to the sun, and all by the 
agency of chlorine. 


823. Coloring matter not a proximate principle, &c. Situation of the 
coloring matter in plants. Means of obtaining these colors. Decompo¬ 
sition of vegetable colors. 



COLORING MATTER. 


359 


824. Several of the metallic oxides, and especially alumina and the ox¬ 
ides of iron and tin form with coloring matter insoluble compounds, to 
which the name of lakes is applied. Lakes are commonly obtained by 
mixing alum or pure muriate of tin with a colored solution, and thus, by 
means of an alkali, precipitating the oxide, which unites with the color at 
the moment of separation. In this property is founded many of the pro¬ 
cesses in dyeing and calico-printing. The art of the dyer consists in giv¬ 
ing a uniform and permanent color to cloth. 

The setting of colors depends on a chemical affinity between the dye, 
and the material with which it unites. To produce this affinity the 
agency of a third substance is often required, which is called a basis or 
mordant.* This unites the coloring matter to the cloth by means of an 
affinity for both. The most important bases or mordants used in dyeing, 
are alumina, and the oxides of tin and iron ; but many others are useful, 
as alum, copperas, sugar of lead, muriate of tin, blue vitriol, &c. 

Colors that adhere to the cloth without the intervention of bases are 
called substantive colors, while those which only form a transient union 
with cloth, unless fixed by a third substance, are called adjective colors. 

Besides bases to fix the coloring matter, various chemical agents are 
employed to alter the shade or hue of colors; thus the muriate of tin 
changes the crimson of cochineal to a brilliant scarlet. Alum changes 
the dull red of madder to a bright crimson. The attraction both of color¬ 
ing matter and mordants for wool and silk, is much greater than for cot¬ 
ton ; thus we find the most brilliant and permanent hues in woollen and 
silken stuffs. All the hues obtained in dyeing, may be produced by four 
primary colors, blue , red , yellow , and black. 

8 25. Blue. The only vegetable substance used for dyeing blue is 
indigo. This is obtained from several species of the Indigofera , 
and has been found in small quantities, in some other plants. 
The indigo plant is a product of warm climates. 

The leaves are fermented with water in large tubs ; the liquor be¬ 
comes acid, and covered with irised pellicles. It is then drained, and 
mixed with lime water. A deposit is formed, which when washed, and 
dried, is the indigo of commerce. In order to obtain perfectly pure 
indigo, it should be heated in a closely covered silver crucible. It soon 
volatilizes and deposits purple crystals. In this state it was found by 
Dumas to consist of 

73.26 parts of Carbon. 

13.81 “ “ Nitrogen. 

10.43 “ “ Oxygen. 

2.50 “ “ Hydrogen. 

100.00 

Pure indigo has neither taste nor odor ; its color is a rich blue, 
with a shade of purple. It does not dissolve in water, alcohol, 

* From mordeo to bite, corrode or fasten upon. 


824. Compounds with coloring matter, called lakes, &c. Setting of 
colors. The use of a moidant. Substantive and adjective colors. Sub¬ 
stances which change the hue of coloring matter, &c. 

825. Indigo, how obtained from the plant ? Its constituent parts. 
Properties of indigo. Effects of deoxygenating indigo. Blue-vat of the 
4yer, &c. Effect of air upon cloth wet in a solution of deoxydized indigo. 




300 


ORGANIC CHEMISTRY. 


or ether. Strong sulphuric acid dissolves it, forming a sulphate 
of indigo, which is employed for giving the color called Saxony 
blue. Where indigo is deoxygenated it loses its fine color, be¬ 
comes yellow, and is easily dissolved in slightly alkaline water ; 
if this solution be agitated in contact with the atmosphere, the 
indigo acquires oxygen, and becomes blue. 

The dyer’s blue-vat is made by mixing indigo with an equal weight of 
green sulphate of iron, twice its weight of lime, and boiling the mixture 
in water.* The protoxide of iron precipitated by lime, gradually deoxi¬ 
dizes the indigo, and a yellow solution is obtained. Cloth wet in this 
liquid, and exposed to the air, becomes green, and then blue by the union 
of the deoxydized indigo with the oxygen of the air ; and the blue indigo 
being now chemically united with the fibre of the cloth, a permanent 
color is obtained. 

A white substance called indogene has been obtained by depriving 
indigo of its oxygen; it rapidly changes to blue on exposure to the oxy¬ 
gen of the air. 

826. Red. Among the red coloring matters are Madder , Cochineal , 
Archil or Litmus , Logwood , Brazil Wood and Safflower. 

Madder is the root of the Rubia tinctorum. It is used in dyeing the 
Turkey-red , and by the aid of proper mordants, may produce not only the 
various hues of red; but purple and black. This is seen when calico 
stamped with different mordants is wet in the madder dye. The coloring 
matter of madder is supposed to have been obtained in a pure state by 
some of the French Chemists in the form of brilliant red, needle-shaped 
crystals. 

Cochineal , though found on the leaves and branches of the cactus 
plant, is an animal substance, deposited by an insect which feeds upon 
it. It is a fugitive dye when mixed with water only ; but becomes fixed 
by alumina, or the oxide of tin. Its natural crimson color is changed to 
scarlet by the per-muriate of tin, or the bi-tartrate of potassa, (cream of 
tartar.) Carmine is made of cochineal and alumina. 

Litmus , Archil, or Turnsol is prepared from the Lichen roccella, a plant 
which grows in the Canary, and Cape de Verd islands. The color of 
the lichen is red; but in preparing litmus by means of fermentation with 
an alkaline substance, it receives a blue tint. This preparation is affect¬ 
ed by the weakest acids, and is therefore much used as a chemical test. 
Paper tinted with litmus is called litmus paper, and furnishes a con¬ 
venient mode of using this as a chemical test. Litmus paper when 
reddened with an acid becomes blue in an alkaline solution. 

Logwood is a heavy compact wood from the Haematoxylum t Cam- 
pechianum, a plant which grows in South America. Its coloring matter 
lias been obtained in crystals called hcmatine. Logwood affords a red, 
fugitive color ; but is chiefly used for black dyes, which are fixed or set 
with iron; copperas (sulphate of iron) is chiefly used for this purpose. 

Brazil Wood is from the Caesalvina echinata a large tree of Brazil. 

Saffloioer is the dried flower of the Carthajnus tinctorius, an unusual 
plant of the countries bordering on the Mediterranean. This is the 

* In the domestic blue dye the ammonia of urine is the solvent of 
indigo. 

t This name is from the Greek haima , blood, in reference to the red 
color of the wood. 


826. Red Colors. Madder. Cochineal. Carmine. Litmus. Log- 
Wood. Brazil Wood. Safflower. Rouge. 




YELLOW DYES. 


361 


exotic compound flower of our gardens, known by the name, Saffron , al¬ 
though the crocus is the true Saffron. The flowers of the Carthamus or 
false saffron are yellow ; but according to Thenard, repeated washing 
dissolves the yellow coloring matter, leaving the red which was com¬ 
bined with it. This article gives a variety of shades of red, from that of 
the damask rose to the cherry. They are fugitive colors though very 
brilliant. Rouge is prepared from this substance. 

827. Yellow. Of yellow dyes the principal are the American 
walnut, turmeric, fustic, saffron, sumach, and quercitron. These like 
the red dyes are all adjective colors. 

The bark of the Walnut , and the Butternut affords a yellow dye, which, 
with iron becomes brown. Turmeric is the root of an East Indian plant, 
the Cucurma longa. Paper stained with an infusion of this dye is called 
turmeric or cucurma paper; it is stained brown by an alkali, for which 
reason it is used as a chemical test. Fustic is obtained from the West 
Indies ; it is the wood of the Morus tinctoria. Saffron is from the Crocus 
sativus. With water and alcohol it forms a bright yellow, which sul¬ 
phuric acid changes blue, then lilac, and nitric acid gives it a green 
shade. Sumach. The bark of the different species of the Rhus, furnish¬ 
es a yellow dye. This was formerly exported in large quantities from 
America to England. Quercitron is the bark of the common black oak 
of this country. A decoction of this bark, gives a bright yellow dye with 
a basis of alumina; with oxide of tin all the shades of yellow from pale 
brown to deep orange. With indigo it forms a green color, and with ox¬ 
ide of iron a drab color. Annotta , improperly called otter , is obtained 
from the seeds of a plant of Cayenne, the Bixa orellana; it is sometimes 
used to heighten the color of cheese, and is much used in domestic 
dyeing. 

Carthamus tinctorius so common in our gardens furnishes a fine though 
fading straw color. It is probable that the foreign species of carthamus 
from which saffron is obtained, differs from the saffron of our gardens. 

828. Black dyes, as writing ink, &c. consist of the salts of iron 
with gallic acid and tannin ; astringent barks, such as maple, 
oak, &c. afford these two substances ; secretions of such barks 
with copperas (sulphate of iron,) will therefore color black. 
Gall-nuts are often used instead of bark to furnish gallic acid and 
tannin. 

There are various mineral dyes as orpiment , the chromates, and 
Prussian blue ; the latter is partly mineral, and partly, an animal com¬ 
pound.* There are various modes of applying the colors in dyeing cloth 
of different kinds. In general, the cloth is passed through a decoction of 
the coloring matter, and then of the mordant; the latter seems to per¬ 
form the same office in preserving a union between the coloring matter 
and the texture of the cloth, as the alkali which affects a combination 
between oil and water. In calico printing “ The mordant thickened 
with gum or flour, is applied to the cloth by means of blocks or engraved 

* To the female enquirers into the coloring matters which may be 
most easily obtained, the author would recommend an article in the Fru¬ 
gal Housewife, of Mrs. Child, entitled “ Cheap Dye Stuffs.” 


827. Yellow dyes. 

823. Mineral dyes. Various modes of applying colors, &c. 

31 * 



362 


ORGANIC CHEMISTRY. 


copper cylinders. The cloth is then passed through a decoction of the 
color which adheres only to the spots impregnated with the mordant, 
and is easily discharged, by washing. To preserve certain parts white, 
they are occasionally covered with wax, tallow or pipe clay, and some¬ 
times the color is discharged from particular parts by chlorine.”— Sill. 


TANNIN. 

829. To the proximate principle called tannin , vegetables owe 
their astringent properties. This principle exists in large pro¬ 
portions in the bark of certain trees, in the gall-nut, and in the 
leaves of the tea-plant. 

The most remarkable property of tannin is that of forming with 
many animal substances, particularly gelatine, a tough insoluble 
and imputrescent compound. Thus the skins of animals, which 
are mostly composed of gelatine, by being soaked in the tan-vat , 
(a decoction of astringent bark,) are converted into leather, 
which is not only necessary to the comfort, and health of man, 
but in various ways contributes to his convenience, and is of ex¬ 
tensive use in the arts of civilized life. Another important 
property of tannin is its action on the salts of iron, which it pre¬ 
cipitates, producing in combination with gallic acid, ink and black 
dyes. 

830. Pure tannin is obtained with difficulty owing to its tendency to 
form combinations with the principles with which it is associated. It 
may be precipitated from an infusion of nut-galls by various re-agents ; 
as sulphuric and muriatic acids, carbonate of potassa, and muriate of tin. 
The precipitate of tannin is combined with other matters, which are sep¬ 
arated by various complicated methods. Some gallic acid and extractive 
matter will often be found after the most careful preparation. Proust 
recommends preparing tannin by precipitating it from an infusion of nut- 
galls, by muriate of tin, washing the precipitate, and passing over it a 
current of sulphuric hydrogen, filtering and evaporating the liquor. 
Tannin tolerably pure may be obtained by precipitating it from an in¬ 
fusion of nut-galls, with lime-water. Pure tannin is without color, very 
soluble in water, but insoluble in perfectly pure alcohol. The acids, ex¬ 
cept the acetic, precipitates it from its solution in water. Tannin is most 
abundant in the inner layers ot the bark of hemlock, oak, chestnut and 
birch. 

831. Artificial tannin , a substance resembling tannin may be produced 
by the action of diluted nitric acid on oil, or indigo ; or by the diluted 
sulphuric acid with the resins, or charcoal. A solution is thus obtained 
which, when evaporated to dryness, produces a brown, fusible substance, 
soluble in water, and insoluble in alcohol, and which exhibits, with a salt 
of iron, and a solution of gelatine the same changes as natural tannin. 


829. Cause of the astringent properties of plants, &c. Action of tan¬ 
nin with gelatine. Leather. Action of tannin on the salts of iron. 

830. Extraction of pure tannin. Properties of pure tannin. 

831. Artificial tannin. Constituent elements of tannin. 



GLUTEN. 


363 


Lagrange asserts that tannin changes into gallic acid by the absorption 
of oxygen. According to Berzelius tannin consists of 
Carbon, 51.160 parts. 

Oxygen, 44.654 “ 

Hydrogen, 4.186 “ 

100.00 

GLUTEN, YEAST, VEGETABLE ALBUMEN. 

832. Gluten is obtained in the process for the separating the 
fecula or starch from wheat flower by washing ; the albumen 
and sugar lodged in the interstices of the gluten are dissolved and 
carried off with the fecula; the gluten is pure when it no longer 
disturbs the transparency of water by washing. It is of a gray¬ 
ish white color, soft, viscous, very tenacious, and elastic. When 
dried it becomes brown, and has a glossy brittleness. Exposed 
to the moist air it swells, putrifies and diffuses an odor like that 
of cheese. It does not dissolve in cold water or alcohol; warm 
water destroys its tenacity and elasticity but without dissolving 
it. It is soluble in most of the vegetable, and some of the min¬ 
eral acids. Charcoal, sulphuric and nitric acids act upon it, as 
with most animal substances. 

833. Taddei, an Italian Chemist, does not regard gluten as a proximate 
principle, but as formed of two such principles, which he calls gliadine * 
and Zimome.t Berzelius, however, supposes the gliadine to be modi¬ 
fied gluten, and the Zimome to be albumen. The Italian Chemist, in 
his researches, discovered that the powder of gum guaicum afforded a 
delicate test for the Zimome ; as, when rubbed in a mortar with this sub¬ 
stance in a moist state, it strikes a fine blue color. This test is found 
equally good to shew when flour contains the due proportion of albumen 
or gluten ; it is kneaded into the flour, which, if good, assumes a blue 
color. But if the flower be bad, owing to the spontaneous decomposition 
of gluten, the blue tint is scarcely visible. 

834. Gluten appears to promote fermentation. The action of yeast 
has been ascribed to its presence. It is favorable to animal nu¬ 
trition. Thus bread is emphatically called the u staff of life.” 
The different kinds of grain contain a large proportion of gluten, 
but wheat more than any other. The gluten in wheat flour, on 
account of its elastic, and viscous nature is favorable to the for¬ 
mation of light bread. The carbonic acid gas which is disenga¬ 
ged during the fermentation, being detained by the gluten, ex- 

* From the Greek glia, gluten. 

t From zume, a ferment or yeast. 


832. Manner of obtaining gluten. Its properties, &c. 

833. Gliadine and Zimome. Test for Zimome and albumen in flour. 

834. Gluten favorable to fermentation, &c. Rye flour and Indian 
meal contain little gluten. 




364 


ORGANIC CHEMISTRY. 


pands it, and causes the pores which appear in light, wheaten 
bread. Rye bread can never be made so light as wheat, because 
rye contains little gluten ; and Indian meal without intermixture 
with some other substance can scarcely be raised at all by yeast. 

835. Potatoes contain no gluten, but much farina, and may be 
mixed with wheat flower in making bread ; but, if added in too 
large proportion, the bread will be heavy, because, for want of 
sufficient gluten to retain the gas of fermentation, the latter passes 
off in the atmosphere ; and if, as supposed, gluten assists fermen¬ 
tation, there will be the less gas disengaged. This substance 
was discovered by Beccaria an Italian Chemist, who, from its 
analogy to glue, both in its viscid properties, and its tendency to 
putrefy, like animal substances called it gluten. 

836. Yeast is a viscous, frothy substance which rises to the sur¬ 
face of fermenting liquors. It is vulgarly called emptins, as when 
beer is drawn off, it is found at the bottom, or in the emptyings 
of the cask. When liquor is fermenting, the yeast rises to the 
surface with the gas it generates; but it afterwards becomes 
specifically heavier than the liquor, and sinks. 

The yeast of breweries, and distilleries is best for raising bread. But 
when this cannot be obtained yeast may be prepared by adding a small 
quantity of ferment to a decoction of hops ; the fermentation is hastened 
by thickening the decoction with flour. Yeast made of a suitable con¬ 
sistency, and dried in thin cakes in the sun, or in an oven, may be long 
preserved. When wanted for use pieces of these cakes are put into 
warm water, which soon ferments, and acquires the properties of new 
yeast. Boiling water, or heat equal to it, destroys the fermenting pow¬ 
er of yeast. Thus the housekeeper learns to be cautious not to scald her 
yeast with the warm milk or warm water with which she mixes bread. 
The cause of the action of yeast in producing fermentation has not been 
discovered. By distillation it affords carbon, hydrogen, and some nitro¬ 
gen ; it resembles gluten in its composition. 

837. Vegetable Albumen , a substance resembling animal albu¬ 
men, and especially in its property of coagulating with heat, has 
been discovered in the almond, and some other oily seeds. It 
contains nitrogen, and when exposed to the moist air, undergoes 
the|putrefactive fermentation, emitting an offensive odor like that 
of old cheese, and disengaging ammonia. Vegetable albumen 
and gluten appear to form a connecting link between vegetable 
and animal substances. 

838. There are many vegetable principles which have not yet received 

835. Effect of mixing potatoes with wheat flour in making bread. 
Discovery of gluten and derivation of the name. 

836. Yeast, &c. Domestic yeast. Dried yeast. Effect of heat on yeast. 

837. Vegetable albumen. 

838. Asparagin. Fungin. Legumin. Ulmin. Caffein. Bassorin. 
Cathartin. Suberin. Lupulin. Piperin. Oliville. Rheubarbarin and 
Rein. Sarcocoll. Pollenin and Medullin. Colocynthis. Polycroite. 
Nicotin. Dahline and Inulin. 



355 


ASPARAGIN, ETC. 

a classification, owing to their not having been sufficiently studied, or to 
some obscurity in the nature of their constitution. We will notice some 
of the most important. Jisparagin has been discovered in the juice of 
the asparagus, with an acid called aspartic; both substances crystallize ; 
and both, by decomposition, afford ammonia, which proves that they con¬ 
tain nitrogen. Asparagin exhibits neither acid nor alkaline properties. 
It is found also in the juice of liquorice, and the Althea officinalis or marsh¬ 
mallows. Fungin is that portion of the fleshy part of the mushroom 
which remains after removing every thing soluble by digesting in alco¬ 
hol, and alkaline water. It is very nutritious,—has a smell like bread, 
but appears to resemble animal matter in its composition. Legumin is 
extracted from the pulp of peas. Its solution gives, with sulphate of 
lime, a dense coagnlum, which is supposed to explain why peas boiled in 
hard water, or that containing a salt of lime, become hard. Peas and 
beans are found to consist of 18.40 per cent of legumin with 42.58 of 
starch, 8 of water, 4 of nitric acid, and 8 animalized matter, &c. Ulmin 
was discovered by Vauquelin in the brown matter which exudes from the 
elm, (Ulmus.) Beaconnot found it in turf and mould. It has been re¬ 
garded by some Chemists as an acid, and called ulmic acid. Ammonia 
and oxygen change gallic acid into ulmin. Caffein is a white, crystalline 
matter extracted from coffee. Pelletier regarded it as a salifiable base ; 
but it neither affects blue vegetable colors, nor combines with acids. 
Bassorin was first extracted from gum Bassora, a substance resembling 
gum tragacanth, and imported from Bassora in Asia. It has been found 
in assafoetida, and some other resinous plants. Cathartin is a substance 
which has been obtained from senna and is supposed to contain the ca¬ 
thartic principle of that plant. Suberin is a name applied by Chevreul to 
the cellular tissue of the cork tree (Quercus Suber,) which he supposes to 
be a proximate principle; the cells of this substance are filled with as¬ 
tringent, coloring, and resinous matter; the latter, Chevreul called 
cerine. By the action of nitric acid, suberin changes to suberic acid. 
Lupulin is obtained from the membraneous scales of the pistillate flower 
of the hop. It is very bitter, and soluble in water and alcohol. Piperin 
is procured from black pepper (piper nigrum); it has some of the stimula¬ 
ting properties of pepper ; these being found to reside in a volatile oil. 
Oliville extracted by Pelletier from the gum of the olive tree, has a bitter 
and aromatic taste. Rhubarbarin is a name given to an extract of the 
medicinal rhubarb, supposed to contain its active principle. Sarcocoll , 
from a plant of Ethiopia and Persia called the Pencea sarcocolla , is im¬ 
ported in small grains, resembling gum arabic. It forms mucilage with 
water; it differs from gum in being soluble in alcohol, and by being 
precipitated by tannin from its aqueous solution. It has a sweetish taste, 
resembling that of liquorice. Pollenin. The pollen of tulips was found 
by Professor John, to constitute a peculiar principle, of a very insoluble 
nature, highly combustible, burning with a rapid darting flame. It has 
been used in theatres for artificial lightning. The same Chemist dis¬ 
covered a peculiar substance in the pith or medulla of the Sunflower, 
which he called medullin This substance yields ammonia by distructive 
distillation. Colocynthin , a name given by Vauquelin, to a bitter, resinous 
extract from the colocynth in which the medicinal properties of the plant 
reside. Polycroite is obtained from the flowers of the saffron (Crocus sa- 
tivus.) It is ‘he coloring matter of the saffron; it is named from polus, many, 
and kroma color, on account of its producing different colors with acids. 
Nitric acid gives it a green color, which disappears on diluting it with 
water. Sulphuric acid, at first, changes it blue, which color gradually 
passes to violet. JYicotin is a peculiar principle obtained by Vauquelin 


366 


ORGANIC CHEMISTRY. 


from tobacco (Nicotiana tabaccum.) It has the smell and taste of the 
plant, is volatile and poisonous. Professor Silliman says, “ The empy- 
reumatic oil of tobacco, disengaged in smoking, is doubtless nicotin 
modified and perhaps rendered more noxious by the heat.”* Dahline 
exists in the tubercles of the Dahlia. It resembles starch in most of its 
properties. Dahline exists with inulin in the Jerusalem artichoke, both 
substances are varieties of fecula or starch, and are therefore nutritious. 
The Dahlia root, if as common as the potatoe, might, therefore form a 
valuable aliment. 

839. Chlorophile is a name given by Pelletier and Caventon to the 
green coloring matter of plants, formerly called green fecula of plants. 
It is obtained by coagulating the green juice of plants with heat, and 
purifying the coagulum with water and alcohol. It is a deep green, 
resinous substance. From some late discoveries it appears that the resin 
may be removed by ether, after which, according to some Chemists the 
coloring matter will be left pure.t Bitter principle. This term was for¬ 
merly applied to a supposed peculiar substance which caused the bitter¬ 
ness of plants. But it is found that different principles in different plants 
produce this effect; thus the bitter principle of the hop is owing to 
lupulin, that of opium to morphia, &c. Extractive matter. This term was 
formerly supposed to refer to a peculiar principle ; but it is vague and 
indefinite, since no suck distinct principle has ever been obtained. 
When vegetable substances are macerated in water, there usually re¬ 
mains, after removing the proximate principle, something which seems 
to belong to none of these principles; and this has been called extractive 
matter. It is a convenient term, which expresses a mixture of different 
principles ; or the residuum of vegetable infusions and decoctions. 


LECTURE XXXV. 

FERMENTATION. 

840. By fermentation is understood a spontaneous change 
which takes place in substances ; their elements disunite, com¬ 
bine in other proportions, and give rise to compounds, differing 
wholly from any which had originally existed in the fermenting 
mass. 

* “Asa source of refreshment and pleasure to man, tobacco ought to 
be universally proscribed; it should be retained only as a means of de¬ 
stroying insects and vermin, and as a medicine, which, in its internal use 
is so violent and dangerous, that the proper occasions for employing it 
must be “ few and far between.”— Sil. El. of Chem. Vol. 2. p. 509. 

t Is there not an inconsistency in those Chemists who talk about a 
pure coloring matter? Since color is itself a mere secondary property 
of matter, and cannot exist separate from a colored body ? Can they ex¬ 
pect ever to obtain a substance of which they can say, This is pure color f 
or even pure coloring matter ? 

839. Chlorophile. Bitter principle. Extractive matter. 

840. What is meant by fermentation ? Different kinds of fermentation. 




FERMENTATION. 


367 


There are various kinds of fermentation ; as the panary which 
produces bread, the saccharine which affords sugar, the vinous in 
which sugar is converted into alcohol, the acetous which results 
in vinegar, and the putrefactive which results in the entire disso¬ 
lution of organic matter. 

841. Panary* ox Bread Fermentation. It is evident that bread 
or even raised dough differs essentially from a mixture of flour 
and water which has not undergone a process of fermentation. 
Besides the porous and spongy texture which distinguishes the 
former, it has a peculiar pungent odor, so that on opening a mass 
of thoroughly raised dough, an effluvia issues scarcely less pen¬ 
etrating than that of ammonia. Dough is not only enlarged in 
bulk by fermentation, but, when subjected to the heat of the 
oven, it swells to a still greater bulk, and appears in the form of 
light bread ; while dough that has not passed through the fer¬ 
menting process does not rise in the oven, and would, if baked, 
present a compact, heavy, insipid and indigestible mass. 

842. It is to gluten that flour owes its property of forming a paste with 
water. Paste is merely a viscous and elastic tissue of gluten, the cells of 
which are filled with starch, mucilage, sugar, &c. This being under¬ 
stood, we can readily conceive, that to gluten, paste owes its property of 
becoming light when mixed with yeast. The yeast acting upon the 
farina or starch of the flour converts it into a gummy, sugarlike substance. 
This saccharine fermentation is the first stage in the process. The change 
of sugar into alcohol and carbonic acid next takes place, and this vinous 
fermentation is the second stage. If the process is suffered to go on, alco¬ 
hol is converted into active acid or vinegar, and this acetous fermentation 
works a third stage. 

At the second or vinous stage of fermentation, a large portion of car¬ 
bonic acid is disengaged. This in seeking to escape becomes fixed in the 
cellular tissue of the gluten, which being tenacious and elastic extends 
itself, forming a series of membranous partitions filled with gas, and thus 
swelling out the mass. When exposed to heat, as in baking, the gas 
expands still more, and the baked loaf becomes specifically much lighter 
than before. 

843. It is very necessary in making bread to observe; 1st. That the 
yeast should be mixed thoroughly with the dough ; otherwise the bread 
will be heavy in certain portions. 

2d. The dough will rise light in proportion to the quantity of gluten 
contained in the flour; for this reason wheat flour makes better bread 
than any other. 

3d. Substances which contain no gluten cannot be raised with yeast. 
Thus the flour of Indian corn, cannot by itself make light bread ; it may 
be advantageously mixed, in certain proportions with wheat or rye ; and 
potatoes though they are nutritious on account of the farina which they 

9 

* From the Latin panis , bread. 

841. Changes effected in flour by means of the panary fermentation. 

842. Importance of gluten in flour. Stages in panary fermentation. 
Cause of the porous texture of bread. 

843. Considerations important in respect to the making of bread. 




368 


ORGANIC CHEMISTRY. 


contain, can never be used for bread, except with the flour of the glutin¬ 
ous grains. When bread has been suffered to sour, or undergo the 
acetous fermentation, the acetous acid which is generated may be neu¬ 
tralized by a solution of pearlash, or some other carbonated alkali, and 
the further disengagement of carbonic acid gas, by the union of its base 
with acetic acid will render the bread still lighter, though there will be 
danger of an alkaline taste, and a yellow or greenish white color. 

844. Saccharine Fermentation. This is that kind of fermentation 
which produces sugar in bodies where it did not previously exist. 
It is observed in the germination of many buds, in heating starch 
with sulphuric acid, and in the action of yeast, or gluten upon 
farina. When starch, which has been changed to a jelly by 
boiling water, is kept moist during some time, a spontaneous 
change takes place and sugar is produced. The germination of 
the buds of barley, in the malting process is an example of the 
saccharine fermentation. u The ripening of fruit has been re¬ 
garded as the effect of this fermentation. But according to 
Proust, who examined the unripe grape in its different stages to 
wards maturity, the process of ripening appears to consist in the 
conversion , not of starch but of acid into sugar. He found that 
the green fruit contains a large quantity of free acid, chiefly the 
nitric, which gradually disappears as the grape ripens ; while its 
place is occupied by sugar. It is hence probable that the ele¬ 
ments of the acid itself, as the result of a vital process are made 
to enter into a new arrangement, by which sugar is generated.”— 
Turner. 

Vinous or Alcoholic Fermentation. 

845. This fermentation takes place when sugar, or farina, 
(which is readily changed to sugar,) together with water and a 
small portion of yeast is exposed to a temperature from 60° to 
80“ F. The liquor soon begins to exhibit marks of action ; 
bubbles of carbonic acid, attracting around them small portions 
of the yeast, form a froth on the surface ; the liquor, after a 
time, deposits the interposed substances, which disturbed it, and 
becomes clear. The sugar having disappeared, it is probable 
that it has been converted into alcohol and carbonic acid ; es¬ 
pecially as the weight of the two latter is found to be about 
equal to the weight of the sugar. 

This process may be examined by way of experiment, by placing about 
five parts of sugar, with twenty parts of water, and a very little yeast in 
a glass flask with a bent tube, the extremity of which opens under an in¬ 
verted jar, full of water or mercury, and exposing the whole to the prop- 

844. What is saccharine fermentation, and when does it take place ? 
Sugar produced in the ripening of fruits. 

845. Production of the vinous fermentation. Phenomena attending 
this fermentation. Experiment to illustrate the process of vinous fer¬ 
mentation. Change of sugar to alcohol. 



FERMENTATION. 


369 


er temperature. The carbonic acid gas which is disengaged may thus 
be collected, and its weight, together with that of the alcohol which is 
now formed in the flask, may be readily ascertained. The quantity of 
yeast decomposed is so small as not to be brought into the account ; the 
only part the yeast performs is that of exciting the fermentation ; the 
agency of atmospheric air is of no importance, as the operation proceeds 
equally well without it. 

According to Gay Lussac sugar may be transformed into alcohol, by 
taking from the former one volume of oxygen gas and one volume of the 
vapor of carbon, constituting, by their union, one volume of carbonic 
acid gas. 

846. Many vegetable juices containing sugar, acids, mucilage 
and starch undergo the vinous fermentation without yeast. This 
is ascribed to the presence of gluten, which seems, in many re¬ 
spects, analogous to yeast. Cider is thus obtained by the fer¬ 
mentation of the juice of the apple, wine from that of the grape, 
current, gooseberry, &c. In the malting of barley, the grain, af¬ 
ter being soaked, is spread upon a floor. When the saccharine 
fermentation begins, and the seed germinates ; the process is 
now interrupted by heat, and the barley remains in a saccharine 
state ; it is now called malt. When malt is fermented with an 
infusion of hops, the liquid is called beer, ale, or porter, all of 
which produce alcohol during the fermentation. Ale and beer 
are more liable to sour than wine, on account of the mucilage 
and other principles which the former derives from malt. Alco¬ 
hol may be obtained by distilling both the liquors produced by 
the vinous fermentation of saccharine fruits and those which re¬ 
sult from the fermented decoction of hops and malt. 

Acetous Fermentation. 

847. The vinous fermentation readily passes to the acetous , 
or that in which acetic acid is generated. The acid appears to 
result from a change in the constituent principles of the alcohol. 
That this change takes place, seems evident from the disappear¬ 
ance of the alcohol, and the simultaneous production of acetie 
acid in an equal proportion to the alcohol which had previously 
existed. Pure alcohol, mixed with yeast and exposed to a warm 
temperature, will undergo the acetous fermentation. The na¬ 
ture of the chemical action which thus changes alcohol into ace¬ 
tic acid is yet considered doubtful. It is necessary to distinguish 
between the mere formation of acetic acid , and the acetous fer- 


846. Vinous fermentation produced by gluten. Malt, &c. 

847. Cause of the change from the vinous to the acetous fermentation. 
In what case pure alcohol may be made to undergo the acetous fermen¬ 
tation. Distinction between the formation of acetic acid, and the ace¬ 
tous fermentation. 


32 



370 


ORGANIC CHEMISTRY, 


mentation. Most vegetable substances yield acetic acid when 
they undergo spontaneous decomposition. Mucilaginous sub¬ 
stances, even when excluded from the air, gradually become 
sour. But these processes appear essentially different from the 
proper acetous fermentation, when there is a visible movement 
in the liquid, with absorption of oxygen, and disengagement of 
carbonic acid. 

848. The acetous fermentation is attended by the following circum¬ 
stances. When a vinous liquor is exposed to the air at a certain tem¬ 
perature, it yields a portion of its carbon to the oxygen of the air, from 
whence results carbonic acid gas, and a slight disengagement of caloric ; 
the liquid becomes turbid owing to the formation of a filamentous matter, 
which, after much agitation, subsides in a jelly-like mass; the alcohol is 
decomposed, becomes transparent, and is found changed to vinegar or 
acetic acid. The alcohol has been supposed to pass to the state of acetic 
acid, by yielding a portion of its hydrogen and carbon to the oxygen of 
the air forming carbonic acid and water, and leaving its remaining car¬ 
bon, hydrogen and oxygen in the exact proportion for forming acetic 
acid. But according to the experiments of De Saussure, the volume of car¬ 
bonic acid gas formed, is such as to show that all the oxygen absorbed 
from the air has united with the carbon of the alcohol, while the hydro¬ 
gen must have been disposed of in some other way than by combining 
with oxygen to form water, as is supposed upon the former theory. 

Putrefactive Fermentation. 

849. While organized beings possess life, the elements of 
which they are composed, remain combined according to the 
laws of the vital principle, which are often contrary to those of 
affinity ; but when life is extinct, the laws of affinity prevail, 
and former combinations are broken up in the effort of the ele¬ 
ments to unite according to their chemical attractions. This 
movement of the particles of bodies is called putrefaction , or the 
putrid fermentation. It is more rapid in animals than in vegeta¬ 
bles ; and more rapid in vegetable substances in proportion as 
their constitution resembles that of animal matter. A damp 
and stagnant air, and warm temperature, hasten the progress of 
this fermentation. When vegetables deprived of their living 
principle, are thus situated, they become converted into a black 
matter called mould, disengaging at the same time a little oil, 
acetic acid, water, nitrogen, carburetted hydrogen, and carbonic 
acid. Animal matter under the same circumstances besides 
most of these products, gives ammonia, some nitric acid, and 
hydro-cyanic acid. All the gases which are disengaged carry 

848. Circumstances which attend the acetous fermentation. 

849. Change which ensues in organic beings when life ceases, &c. 
Phenomena of the putrefactive fermentation. Products of this fermen¬ 
tation. Miasma of marshes, &c. 



ANIMAL CHEMISTRY. 


371 


with them a little decomposed animal matter, which gives them 
a very offensive odor. The noxious miasma of marshes is sup¬ 
posed to be a gaseous principle, arising from the putrefactions 
of vegetable matter. They have never been obtained in an in¬ 
sulated state, and it is not known even whether they are a dis¬ 
tinct principle of matter, or not. 

850. The dark mould arising from putrefactive fermentation 
enriches soils, and fits them for the production, and nourishment 
of new plants. Thus, in the vegetable kingdom, we everywhere 
behold decay followed by renewed life. Why then should man 
fear to commit his organic part to the dissolution of the sepul¬ 
chre, and the watchful eye of that Omniscient Power to whom 
every atom is known, and who can as easily reassemble the dis¬ 
persed elements, as he could at first have made man of the dust 
of the earth ? And why should infidel man speculate upon the 
ability of the Almighty to raise the dead, because the atoms 
which composed these bodies, have successively held a place in 
other material forms ? Having seen the powers of chemistry 
to form of a little portion of matter a body ofwonderfully increas¬ 
ed magnitude, shall we dare restrict the power of The Great 
Chemist of the Universe, to form even of one minute atom, 
one little gem which may constitute our personal identity, that 
u celestial body ” which is to be fashioned like unto His glorious 
body, immortal and incorruptible !” 

Note. 

For an account of the chemical phenomena attending the germination , 
growth , respiration, &c. of plants, the student is referred to the author’s 
“ Familiar Lectures on Botany,” where these subjects are discussed at 
large. 


LECTURE XXXVI. 

ANIMAL CHEMISTRY, OR ANIMAL ORGANIC BODIES. 

851. Animals, like vegetables, are composed of different parts ; 
these parts of different animal substances ; and these substances, 

850. Reflections on the new life which results from putrefactive fer¬ 
mentation. 

851. Composition of animals. The object of animal chemistry. Dif¬ 
ference between the proximate animal principles and the vegetable prin¬ 
ciples. 




372 


ORGANIC CHEMISTRY. 


of different proximate principles. The object of animal, like that 
of vegetable chemistry, is to examine into the nature of those 
proximate principles, and their associations in the different sol¬ 
ids and liquids of animals. 

We do not find in the analysis of the proximate animal prin¬ 
ciples, any new ultimate elements. These proximate principles 
differ from the vegetable principles in containing more nitrogen, 
in a stronger tendency towards putrefactive fermentation, and in 
giving off, during this process, those offensive odors. 

852. On exposing animal substances to heat in close vessels, 
which is called destructive distillation , we learn the nature of 
these ultimate elements. These, in some cases, as in animal 
oil, are the same as we obtain in the destructive distillation of 
vegetable matter ; but, generally, nitrogen in greater quantity is 
obtained and sometimes a little phosphorus and sulphur. The 
ultimate elements of animal matter may be, in general terms sta¬ 
ted as nitrogen, hydrogen, carbon and oxygen. 

853. It is no more possible for man to recompose animal, than 
vegetable substances, they are formed by the various operations 
of a living principle, as respiration, circulation, and nutrition, se¬ 
cretion, &c. 

The proximate animal principles are less numerous than the 
vegetable. They may be divided into three classes. 

ls£. Neutral principles, or those that are neither fat nor acid. 

2d. Animal acids. 

3 d. Animal substances which are fat, without being acid. 

4th. Saline and earthy matters. 

854. The first division includes fibrin, albumen, gelatine, 
&c. These principles contain a large proportion of carbon : and 
their hydrogen is in the proportion to take up all their oxygen to 
form water, and all their nitrogen to form ammonia. But in de¬ 
structive distillation these elements are obtained under a variety 
of combinations; as some water, carbonic gas, carbonic oxide, 
carbonate, and hydro-cyanate of ammonia, a thick, black, and 
foetid oil, carburetted hydrogen, nitrogen, and a bulky carbona¬ 
ceous matter which remains in the retort. This carbonaceous 
matter is more effectual as a clarifying agent than vegetable char¬ 
coal, and is less easily consumed on account of its containing 
some phosphates, and perhaps oxides of iron and manganese. 

855. Fibrin, is that part of animal muscle which gives the 
power of motion, by alternate contraction and relaxation. It 


852. Destructive distillation. Ultimate elements of animal matter. 

853. Animal substances cannot be recomposed. Four classes of prox¬ 
imate animal principles. 

854. Substances included in the first class, &c. 

855. What is fibrin? 



ANIMAL ALBUMEN. 


373 


constitutes the greater part of muscular flesh; and appears to be 
that substance immediately acted upon by the nervous matter 
which is supposed to communicate directly with the sensorium 
or brain, from whence emanate the impulses which produced vol¬ 
untary motion. Fibrin constitutes a large proportion of the 
blood, and exists in other animal fluids. 

856. Pure fibrin is without taste or odor, of a yellowish color, and 
semi-transparent. It is capable of absorbing a portion of water, in which 
state it is white, flexible and elastic. Alcohol and ether softens and in 
time renders it pulpy. Weak muriatic and sulphuric acids combine with 
it; concentrated nitric acid decomposes it. It dissolves in cold alkaline 
solutions ; and decomposes in the same with heat. 

Fibrin may be obtained by beating blood, recently obtained from the 
veins, with a bundle of twigs ; it attaches itself to the sticks under the 
form of long, reddish filaments, which become colorless by repeated 
washing with cold water. It should be dried in the open air. Accor¬ 
ding to Gay Lussac and Thenard it is composed of 

53.360 parts of Carbon. 

19.934 “ “ Nitrogen. 

19.685 “ “ Oxygen. 

7.021 “ “ Hydrogen. 

100.000 

I 

• 

These proportions when reduced to equivalents , have been thus stated 
by Dr. Hare. 

Carbon 18 equiv.=108. 

Nitrogen 3 “ =42. 

Oxygen 5 “ =40. 

Hydrogen 14 “ =14. 

Equiv. of fibrin =104. 

857. Animal Albumen. The purest form in which albumen is 
known to exist, is in the white of eggs ,* though here it is united 
with some water, a little soda, sulphur and some salts. The free 
soda contained in the albumen of the egg is sufficient to green, 
slightly, blue vegetable infusions. 

Albumen exists in most of the animal solids and fluids. It is 
the germ of all animal matter ; cartilage, bones, hair, shell and 
horn are formed from it, and it exists in the skin, membranes, 
and muscles. In a liquid state it exists in chyle, and blood ; in 

* The word albumen was first applied only to distinguish the white of 
the eggs. 


856. Properties of fibrin, &c. How obtained? Constituent elements 
of fibrin, &c. 

857. Purest form of albumen. Its extensive existence in animals, and 
animal matter. Peculiar property of albumen. 

32 * 




374 


ORGANIC CHEMISTRY. 


the coagulable parts of milk, or that which becomes cheese, and 
forms a part of various other animal fluids. 

Albumen is heavier than water, and perfectly soluble. Its 
peculiar property is that of coagulating by heat, alcohol, and 
strong acids. 

Water heated to the boiling point will harden the albumen of 
an egg in four or five minutes. 

858. It is the property of coagulating, which renders albumen useful 
in clarifying liquors. Thus blood, which contains a large portion of al¬ 
bumen is used to clarify the syrup in the manufacture of sugar. And 
the use of the white of eggs to clarify liquor for jellies and preserves is 
common in culinary operations. In these cases the albumen, mixed in a 
very small proportion with the liquors, coagulates by heat and entangles 
in its substance all the sediment, or undissolved particles, which it car¬ 
ries to the surface of the liquid where they form a scum which may easi¬ 
ly be removed. Albumen is used to clarify wine and cider ; and in those 
cases is coagulated, by the vegetable acids and by alcohol, without heat. 

It resembles fibrin in many particulars ; but dissolves more readily in 
potassa, and soda, with which it forms a soap-like compound. Acids 
precipitate the albumen again in a coagulated state. Phosphoric acid 
does not precipitate albumen, but it is precipitated by pyro-phosphoric 
acid, also by metallic salts, tannin, and corrosive sublimate ; for the lat¬ 
ter it is a very delicate test, causing a visible White precipitate within a 
fluid containing a very small proportion of that pioson. , 

When coagulated by heat albumen becomes insoluble in water. If an 
egg taken from its shell, be put into boiling water, the white does not 
dissolve or mix with the water, because it almost instantly begins to co¬ 
agulate. In about three minutes it is boiled sufficiently for the table. 
Eggs may be thus boiled more delicately for the sick than with the shells 
on ; in the latter case the outer portion of the white may become too 
much hardened, r while the inner part is under done. Fresh eggs are 
full, and therefore do not cook as soon in the shell as those twenty or 
thirty days old, which usually have a little vacuum at one end, owing to 
the escape of moisture through the pores of the shell. In six or seven 
minutes boiling the albumen of the egg becomes solidified, and contin¬ 
ued boiling would but serve to increase its hardness up to a certain point. 
From the insoluble nature of albumen, after being hardened by heat, 
we may infer that hard-boiled eggs, are indigestible food. Cheese, 
which is albumen hardened by pressure and desiccation, is of the same 
nature, and should not be eaten in large quantities. 

There are different views as to the cause of the coagulation of albu¬ 
men. Fourcroy attributed it to oxygenation. “ But,” says Thenard, 
“ albumen coagulates as readily without as with access of air, and in al¬ 
cohol as well as by heat, we must therefore refer this change to cohe¬ 
sion.” The affinity between water and albumen appears slight, and is 


858. Use of albumen in clarifying liquors, &c. Albumen compared 
with Fibrin. Substances which precipitate albumen. Change which 
takes place in an egg when placed in boiling water, <fcc. Opinions as to 
the cause of the coagulating of albumen, &c. Putrefactive tendency of 
albumen in a fluid state, &c. Sulphur in albumen. Test of the pres¬ 
ence of albumen in animal fluids. Composition of albumen as compar¬ 
ed with fibrin. Albumen an antidote to metallic poisons. 




GELATINE. 


375 


diminished by heat, until quite destroyed, the cohesive principle prevails, 
and albumen becomes a solid mass. The union of the water of fluid al¬ 
bumen with alcohol, would produce heat, and this would still further 
promote the decomposition of the albumen. The same cause operates 
when the strong acids are added to albumen: viz, the attraction of those 
acids for water, and the increase of temperature which takes place as 
these two fluids unite. 

Fluid albumen readily putrefies ; this may be observed in the case of 
an egg taken from the shell, when suffered to stand a few days, exposed 
to the air at a warm temperature. Even eggs protected by the shell 
require to be kept in salt, lime, or powdered charcoal, in order to pre¬ 
serve them for any great length of time. Coagulated albumen putre¬ 
fies with difficulty ; it therefore follows that hard boiled eggs may be pre¬ 
served much longer than eggs which have not been boiled. 

Albumen contains some sulphur; thus when blood is suffered to evap¬ 
orate in a silver vessel, the vessel becomes tarnished by sulphuret of sil¬ 
ver ; and the same may be observed of silver spoons with which eggs 
have been eaten. Putrid albumen also gives off the odor of sulphuret¬ 
ted hydrogen. 

Galvanism furnishes an excellent test of the presence of albu¬ 
men in animal fluids. When liquid albumen is exposed to the 
galvanic circuit, pure soda appears in the negative cup, and the 
albumen coagulates in the positive. This effect has been attrib¬ 
uted to the decomposition of muriate of soda ; the muriatic acid 
being thus left free, coagulates the albumen. 

According to different analyses, albumen contains one equiva¬ 
lent more of carbon, hydrogen and nitrogen, and one less of ox¬ 
ygen than constitute the ultimate equivalents of fibrin. On ac¬ 
count of the insoluble precipitate which albumen forms with me¬ 
tallic salts and chlorides, by uniting with their acids, this sub¬ 
stance is recommended as an antidote to poisons of this nature ; 
especially corrosive sublimate and mercurial salts. 

859. Gelatine or Animal Jelly constitutes the greater part of 
the skin of animals ; it is also contained in membranes, mus¬ 
cles, tendons, ligaments and cartilages, and even in bones and 
horns- 

It may be obtained by boiling these substances in water. The gela¬ 
tine dissolves, forming a transparent solution, which, when evaporated 
to a certain degree and cooled, gelatinizes or forms a semi-transparent, 
tremulous solid, as is seen in the jelly made by boiling calves’ feet; this 
is a hydrate, containing a large portion of water, in which it readily 
melts with a slight degree of heat. By continued evaporation it hard¬ 
ens, loses its transparency, and acquires a vitreous appearance. Glue is 
gelatine thus prepared, and is procured by boiling the skins and hoofs of 
animals. The Size used by paper-makers is glue much diluted ; it is used 
to give the paper a smooth surface, and prevent ink from spreading. Pa¬ 
per without sizing is sometimes called bibulous or blotting paper, be¬ 
cause it readily absorbs moisture. 


859. What parts of animals contain gelatine? How obtained. Glue. 
Paper maker’s Size. Isinglass. Calves’ foot jelly, &c. Portable Soup, 
&c. Gelatine with alcohol, sulphuric acid, &c. 




376 


ORGANIC CHEMISTRY. 


Isinglass* which is used for blanc-monge and jellies, is gelatine ob¬ 
tained from the sounds of fishes. It is usually pure and white, and be¬ 
ing evaporated to a very dry state, is a concentrated gelatine, requiring 
but a small portion, dissolved in boiling water, to form a gelatinous mass 
when cool. Calves' foot jelly is made by boiling the feet of calves, 
straining and evaporating the liquor, and adding sugar, wine, lemon and 
spices, to give it an agreeable flavor. Hartshorn shavings , or small sha¬ 
vings of the horns of the hart, yield gelatine, which is considered as pe¬ 
culiarly nutritive for the sick. 

When gelatine is distilled, hydrogen and nitrogen unite and form am¬ 
monia; which being at first considered as a peculiar product of the 
hartshorn, by which it is generally best known. 

Portable Soup may be made by boiling meat, or even bones for a 
sufficient length of time, and straining and evaporating the liquor, and 
then drying it in thin cakes, by a slow, gentle heat. These cakes will 
keep for years, and form a very concentrated nourishment. As there is 
a great deal of gelatine in bones, it should be made an object in domestic 
economy to preserve the bones of roast meat for soup. There is a rich¬ 
ness of flavor in soup prepared from such bones, that cannot be given to 
that made from joints of meat that have not been thus cooked. Soup is 
less used in domestic economy than it should be, considering that, on ac¬ 
count of the gelatine it contains, it is one of the most nutritious kinds of 
food, and that those joints of meat which are the least expensive! furnish 
the greatest proportion of gelatine. By means of the strong heat which 
may be applied in Papin's digester, bones are readily dissolved, and their 
nutritious qualities thus extracted. 

Gelatine is insoluble in alcohol, but dissolves in most of the diluted 
acids. Sulphuric acid converts it into a kind of sugar. Common vine¬ 
gar, with a gentle heat, dissolves isinglass, forming with it a cement for 
glass and china. 

Gelatine does not, like fibrin and albumen, form with alkalies soapy 
compounds which may be precipitated by acids ; but it dissolves with hot 
caustic alkali, and forms a brownish viscid substance, without those 
properties. Gelatine differs from albumen in not readily precipitating 
metallic solutions. 

860. Gelatine is remarkable for its property of combining with 
tannin; by this means, the skins of animals are hardened, and 
converted into leather. The skins being freed from hair, fat, 
&c. by various processes are little else than gelatine, bound to¬ 
gether by fibrous matter. Thus prepared, they are laid in vats, 
or solutions of tannin. The latter gradually leaving the water 
forms with the gelatine a firm and insoluble union. By means 
of various improvements, which have been the fruits of chemical 
discovery, the process for tanning leather has been shortened, 
from two or three years, to a few months, or even weeks. 

* Fish glue or ichtkyocol. 

t There are what the butchers call hock bones , or the lower joints of the 
legs of neat cattle which, being abundant in cartilage and tendons, are 
r ich in gelatine. 


860. Action of gelatine with tannin. Skins converted into leather. 
Elements of gelatine compared with those of fibrin and albumen. 



GELATINE. 


377 


Gelatine contains less carbon and nitrogen than either fibrin or 
albumen, and more oxygen and hydrogen. 

Osmazome. 

861. A substance found by Thenard in the muscular flesh of animals, 
and in mushrooms. It is obtained by dissolving small pieces of animal 
muscle in cold water; on boiling the liquor, the albumen vegetates, and 
rises to the surface, from whence it is removed; the remaining liquor, 
W'hen limpid, is filtered, evaporated to a syrup, and healed with strong 
alcohol, which dissolves the osmazome, and precipitates some salts, as 
muriate of soda and potassa. On evaporating the alcoholic solution, 
pure osmazome is obtained. It is of a yellowish brownish color, with an 
agreeable taste and odor resembling that of soap. It is to this substance, 
according to Thenard, that soup owes its flavor ; 1 part of osmazome, as 
is said, being in this compound combined with 7 parts of gelatine. When 
decomposed by heat, osmazome furnishes carbonate of ammonia, and a 
bulky charcoal, which, by burning, yields soda. 

Sugar of Milk. 

862. By evaporating whey the saccharine principle of milk is obtained. 
It is found deposited in compact layers; but may be obtained in semi¬ 
transparent crystals, by re-dissolving it, and purifying the liquor with 
albumen. It is insoluble in strong alcohol; this gives a test for the sugar 
of milk, when used, as it sometimes is, for adulterating the sugar of the 
cane. It is less sweet than vegetable sugar, and does not suffer the vin¬ 
ous fermentation, with water and yeast. According to analyses of this 
animal sugar, it contains no nitrogen, but carbon, oxygen, and hydrogen 
in very nearly the proportions of other sugar. 

Second Class of Animal Substances , or Animal Acids. 

863. By the term animal acids we mean such acids only as 
are the sole result of animal organization, and found only in the 
animal kingdom. 

We shall give but few examples of these acids, as their study belongs 
rather to medical, than chemical science. 

Lactic acid, was discovered by Scheele in sour whey. According to 
Berzelius, it exists in blood. It is a thick, uncrystalizable liquid, solu¬ 
ble in water, and alcohol, and combines with bases, forming soluble salts. 
But the existence of this acid is regarded as uncertain. It has been ever 
doubted by Berzelius whether it may not be acetic acid, united to animal 
matter; or perhaps identical with zumic acid. Formic acid from formica, 
an ant, is extracted from ants. Its specific gravity is greater than that of 
aoetic acid, which it resembles in its properties. Saccholactic or mucic 
acid , is obtained by heating the sugar of milk with nitric acid. But as it 
is now known to exist in gums, and many other vegetable substances, it 
can no longer be regarded, exclusively, as an animal acid. Caseic acid. 
It is this acid that gives to old cheese its peculiar odor. It is of a yel- 

861. Mode of obtaining osmazome. Properties, <&c. 

862. How is sugar of milk obtained ? Alcohol a test. Sugar of milk 
compared with vegetable sugar. 

863. What is meant by the term animal acids. Lactic acid. Formic 
acid. Saccholactic acid. Caseic acid. Butyric, capric, and caproic 
acids. Sebacic acid. Stearic acid, &o. 



378 


ORGANIC CHEMISTRY. 


low color, with a taste like cheese. Nitric acid converts it to oxalic acid. 
It gives ammonia by distillation, is precipitated white, by a secretion of 
nut-galls. It forms with ammonia an uncrjstallizable salt. 

Butyric acid was discovered by Chevreul in butter. It inflames on the 
near approach of a'burning body, does not solidify at 15 c below zero. 
Capric acid has been obtained from butter made of cow’s milk; and 
caproic acid from butter made of goat’s milk. 

Scbacic acid , was discovered by Thenard in the recipient after the dis¬ 
tillation of hog’s lard. It contains no nitrogen. It combines with alka¬ 
lies, forming salts called sebates. 

Stearic , Margaric , Oleic , and some other acids were discovered by 
Chevreul in a series of experiments on animal fat substances. We shall 
notice them, when treating of that class of bodies. 

Third Class of Animal Substances , or Animal Oils or Fat 
Substances. 

864. Bodies of this class are distinguished by peculiar charac¬ 
teristics. They melt at a low temperature, are insipid, very in¬ 
flammable, insoluble in water, and give by distillation, much foetid 
oil, and a small carbonaceous residuum. When their vapor is 
made to pass through a heated tube, much carburetted hydrogen 
is disengaged. They contain no nitrogen, and but a small pro¬ 
portion of oxygen, and form soap with alkalies. These bodies 
are known under various names, as fat, oil, suet, lard, tallow and 
butter. They vary amongst themselves in hardness, and some 
other properties. When an animal substance is boiled, the fat, 
being specificially lighter than water, floats, and may easily be 
removed. In some cases, as in what is called by housekeepers 
the trying of lard, the fat being incorporated with a fibrous tex¬ 
ture, requires to be for some hours exposed to a moderate heat, 
and then strained, in order to separate it from the fibrin. 

865. Train or Fish Oil , is obtained from the blubber of the whale. It 
is the common lamp oil, and is used in making oil gas. It is often so 
impure, as to give an offensive odor in burning. On account of the 
quantity of carbonaceous matter which settles upon the wick in burning 
impure oil, it is unsuitable for argand or astral lamps. The wick becom¬ 
ing encrusted with animal charcoal, its little capillary tubes which 
pumped up the oil and thus fed the flame, are prevented from performing 
their office, and the lamp goes out. This mortification to housewives, 
might be spared, if care were taken to procure good winter strained oil, 
to keep the lamps clean, and to tip the wick occasionally with spirits of 
turpentine, in order to render it more inflammable. Train oil is com¬ 


posed of Carbon, 12 Equiv.=72 per cent. 68.87 

Oxygen, 2 “ =16 “ 16.10 

Hydrogen, 17 “ =17 “ 15.03 


Chem. Equiv. “ 105 100.00 


864. General properties of these bodies, &c. 

865. Train oil, its use, properties, &c. Why unsuitable for astral 
lamps, &c. Composition of train oil, 




ANIMAL OILS. 


379 


866. Spermaceti is obtained from the head of the Spermaceti whale. It 
is found in an oily matter contained within a bony cavity ofthe head and 
not in the brain of the whale. It is put into bags, and subjected to pres¬ 
sure : the part which is fluid and can be strained out at a low tempera¬ 
ture, is called winter strained oii ; this will resist the ordinary cold of 
winter without congealing, and burns without incrusting the wick. 
After the oil has been pressed out of the spermaceti, it is melted, strain¬ 
ed, and washed with a weak solution of potassa ; this is the spermaceti of 
commerce. It is softer and more brittle than white wax, and chiefly 
used for candles. It dissolves with boiling alcohol, and on cooling is 
deposited in the form of brilliant scales, called by Chevreul, cetine. This 
is pure spermaceti. Cetine forms a soap with potassa, which, when de¬ 
composed by an acid, gives rise to a substance called ethal, from a com¬ 
bination of the first syllables of ether and alcohol, to both of which it has 
some resemblance. 

867. Stearin and Elain. It was discovered by Chevreul that 
animal fat, and the fixed vegetable oils are not pure proximate 
principles, but consist of one substance which is hard at common 
temperatures, and another which is fluid. The former he called 
Stearin from the Greek stear , suet, the latter Elain from elaion , 
oil. Beef suet, lard, and butter maintain their solidity at com¬ 
mon temperatures, because they contain a greater proportion of 
stearin than of elain, while oil, in which elain exists more abun¬ 
dantly, is fluid except at very low temperatures. 

These principles were obtained by Chevreul by dissolving pork-fat in 
boiling alcohol; after standing some time, the liquor was decanted, and 
to the undissolved fat was then added a new portion of boiling alcohol. 
The process was repeated until the whole was dissolved. Each portion 
of alcohol, on cooling, deposited stearin in white needle shaped crys¬ 
tals, while elain, which remained in solution, was obtained pure by evap¬ 
orating the alcohol. Elain resembles olive oil in appearance; it is con¬ 
sidered valuable for oiling the wheels of watches, and other delicate 
machinery, as it remains fluid at a very low temperature, and does not 
unite with the oxygen ofthe air to become an acid. 

All fat substances contain stearin and elain, and are firm or soft, in 
proportion as one or the other prevails. Thus hog’s-lard contains stearin 
38 parts, and elain 62, while olive oil contains stearin 28 parts, and 
elain 72. 

Their ultimate elements, are 

Stearin. Elain. 

Carbon 79.030 78.776 

Hydrogen 11.422 11.770 

Oxygen 9.548 9.454 

868. When fat substances are heated with an alkali, a remark- 

866. Spermaceti. Winter strained oil. Spermaceti of commerce. 
Cetine. Ethal. 

867. Discoveries of Chevreul with respect to animal fat, &c. Manner 
in which Stearin and Elain were obtained. Use made of Elain in the 
arts. Proportions of Stearin and Elain. Ultimate elements of Stearin 
and Elain. 

868. Effect of alkalies upon fat substances. In what consists the pro¬ 
cess of forming soap, or saponification ? Cause of the hardness or soft¬ 
ness of soap. 



380 


ORGANIC CHEMISTRY. 


able change appears to take place in the arrangement of the prox¬ 
imate principles. Stearin and elain are decomposed, and these 
elements arrange themselves in several new compounds, called 
margaritic , stearic and oleic acids, and glycerine. The process of 
forming soap consists in the union of the acids with the alkalies 
employed, forming margarate , stearate and oleate of potassa or 
soda. According to Chevreul, to whom science is indebted for 
these discoveries, saponification is the change which fat substances 
undergo in the arrangement oj their elements , by the action of the 
alkali. Those elements having combined, in proportions to form 
acids, unite with the alkali which is presented to them, and form 
salts , which are soluble in water ; and capable of combining with 
it in all proportions. Thus soap is not, as was formerly con¬ 
sidered, a direct combination of oil and alkali, but a mixture of 
various salts resulting from the union of acids and alkali. The 
nature of the compounds formed differ in different kinds of soap. 
That which is made with the fat of pork, beef, &c., contains 
more stearate than that which is made with human fat, the latter 
consisting chiefly of margarate and oleate. 

Soap is hard in proportion to the quantity of margarate or stearate it 
contains, and soft when the oleate prevails. Much also depends upon the 
nature of the alkaline base ; as soda tends to render soap hard, and potassa 
soft. Thus the stearate of soda will form the hardest soap, and the oleate 
of potassa the softest. The hardness of soap is also increased by exposure 
to the air, or evaporation from any cause. 

869. Glycerine is the sweet principle of oils : it is formed by 
the action of metallic oxides, upon fat substances, or in other 
words, during saponification. It may be obtained in the form 
of sweet, uncrystallizable Syrup. 

Adipocine (from adeps, fat and cera , wax) is a white, pearly 
substance resembling Spermaceti, which forms, when human 
bodies are subjected to slow decomposition, under water, or in 
wet places. 

Fourcroy whose attention was first directed to the subject, regarded 
this matter as an ammoniacal soap with excess of fat.* Chevreul by a mi¬ 
nute analysis has found that it consists of some ammonia, potassa and 
lime united with much margaritic acid, (to which it owes its peculiar 
whiteness,) and a little oleic acid. 

It may be obtained by keeping animal muscle, for some 
months in a running stream ; or, more rapidly, by digesting 
the muscle in nitric acid, and then exposing it to the action of 
water. 

* The phenomenon was first observed on opening the graves in the cem- 
etrey of the Innocent, at Paris in 1782. The superstitious regarded it as 
a miraculous testimony to the holy lives of the persons whose 
bodies were thus changed to a pearly white. 


869. Glycerine. Adipocine. 



GASTRIC JUICE. 


381 


Fourth class of animal substances ; or saline and earthy matters , 
and the soft or solid parts of an animal. 

870. All the humors, and many of the soft and solid parts of 
animals contain a certain quantity of saline and earthy matter. 
The phosphate of lime, muriate of soda and carbonate of soda are 
found to be most common. 

No law of animal existence is more admirable than that by 
which food is converted into blood. First the food dissolving in 
the stomach, becomes a pulpy matter, called chyme; the latter 
either passes into the interstices or becomes a milky liquid called 
chyle. The chyle forms blood , and the blood is converted into 
the various liquid secretions and solid parts of the body. 

As the subjectsof digestion,circulation^ and respiration belong to Physiolo¬ 
gy rather than to elementary chemistry, we shall not here attempt 
to enter into their investigation. 

871. By secretion is understood a process, in which any particu¬ 
lar organ, by decomposing blood, forms a substance peculiar to 
that organ. It is thus that all animal fluids, except the chyle and 
blood are formed. Most of the fluids of secretion remain in the 
body, and then fulfil some peculiar office. 

872. The bile is a bitter, yellowish-green secretion, formed in 
the liver, from venous blood. By mixing with the chyme in the 
stomach, it acts an important part in converting it into chyle, and 
is also a necessary stimulus to the bowels'. Human bile consists 
of a bitter resin , albumen , soda , some of the salts of soda , as the 
sulphate, phosphate and muriate, oxide of iron , and a large propor¬ 
tion, (about 90 per cent) of water. In diseased persons the 
proportion of resin is less, and that of albumen greater, than 
in those who are in health. A peculiar substance, called picro- 
mel* has been discovered in human bile, in that of the ox and 
some other animals ; and it is supposed to exist in all. It is of 
consistence of turpentine, of a bitter taste, and without odor. 

873. Gastric juice is a secretion of the stomach, and the prin¬ 
cipal agent in digestion. It has a saline taste, and does not 
give either the acid or alkaline test with vegetable colors. 
Though apparently a mild, neutral liquid, it possesses a remark¬ 
able solvent power. When food is introduced into the stomach 

* From the Greek pier os , bitter, and mege , honey, so called from its 
peculiar taste. 

870. Saline and earthy matter found in animal substances. Change 
of food into blood. Chyme and chyle, &c. 

871. Secretion. 

872. Bile. Picromel. 

873. Gastric juice. 

33 




382 


ORGANIC CHEMISTRY. 


it is dissolved by the gastric juice, and changed into the pulpy 
substance, chyme. Experiments made with the gastric juice, 
taken from the stomach of an animal, killed while fasting, have 
proved that this liquid is capable of dissolving very insoluble 
substances ;—and it is known that after death, or in excessive 
fasting, it turns its active energies and seizes upon the coats of 
the stomach itself. 

874. Lymph is a colorless, saltish liquid, secreted in a set of 
vessels, called lymphatic. These vessels have their origin in the 
extremities of the arteries, and extend over the surface of the 
cellular membrane. The liquid formed in them, lubricates the 
various cavities of the body, exists in blisters, and is secreted, in 
large quantities, in cases of dropsy. 

875. Synovia is a viscous fluid, secreted in the capsules of 
the joints, preserving their health and freedom of motion, and 
protecting them from injury. 

976. Saliva is an inodorous, tasteless fluid, secreted from the 
blood, by different glands around the mouth, and discharged into 
it through various ducts. Mixing with food it softens and dis¬ 
solves it, and thus serves an important purpose in digesting. It 
lubricates the organs of speech, and thus enables them to perform 
their office with greater ease. In the analysis of this proximate 
principle, are found salts of various kinds, (chiefly muriate of po- 
tassa,) mucus , albumen , and a very large proportion of water. 
From the mucus existing in saliva, according to Thenard is de¬ 
posited the tartar which incrusts the teeth. 

877. Blood , milk , butter , cheese , tyc., are products which offer 
interesting subjects of enquiry to the student of animal chemistry. 

The brain , skin , glands , tendons , muscles and bones ; — hair , wool) 
nails , teeth, shells , <$c., with various other substances constituting 
either the bodies of animals, or resulting from their organization, 
have been subjected to chemical analysis and though found to 
differ among themselves in their proximate principles, yet they 
consist of a small number of the ultimate elements into which 
Chemistry has resolved all matter, whether of the inorganic or 
organic kingdoms. 


CONCLUSION. 

878. Before taking a final leave of our young students, we 
would call their attention to the effects which the study of the 


874. Lymph 

875. Synovia. 

876. Saliva. 

877. Other subjects connected with animal chemistry. &»c. 

878. Conclusion. 



CONCLUSION. 


383 


useful and noble science of Chemistry should have upon their 
own minds. Chemists have sometimes, most unhappily, been 
led to confound the soul with matter ; and the laws of nature 
with the providence of God. This unhappy result is owing either 
to a narrowness of mind, which cannot rise from effects beyond 
their secondary causes, or a pride of intellect which cannot en¬ 
dure to ascribe supreme power to an unknowm being. The phe¬ 
nomena of nature exhibit to the enlightened and humble Chris¬ 
tian, an all wise and powerful Divinity who presides over, and 
governs all. The regular sequences of natural phenomena, so 
far from indicating the non-existence of a Deity, prove them¬ 
selves to be the laws to which He has wisely subjected all mate¬ 
rial substances. 

The skeptic indeed talks of the laws of nature ; but how absurd 
to suppose the existence of laws, without a lawgiver ! We have 
shewn, in a great variety of applications, the utility of Chemistry 
considered in its economical relations;—but, in taking leave of 
our subject, we would refer to considerations of a higher and no¬ 
bler nature.—We would bid adieu to our science, not merely as to 
an agent subservient to material wants, but as a noble pursuit, 
in which, in addition to the pure and elevated enjoyment arising 
from the acquisition of knowledge, our souls have been raised to 
higher thoughts of God, and a better understanding of his opera¬ 
tions. 








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